Murata Electronics North America 2410M Modular 2.4 GHz Transceiver User Manual Integration Guide

Murata Electronics North America Modular 2.4 GHz Transceiver Integration Guide

Integration Guide

WIT2410

2.4GHz Spread Spectrum

Wireless Industrial Transceiver

Integration Guide

June 15, 1999

One Meca Wa

Norcross, Georgia 30093

www.digital-wireless.com

(770) 564-5540

Note: This device has not been authorized

as required by the rules of the Federal

Communications Commission. This device

is not, and may not be, offered for sale or

lease, or sold or leased, until authorization

is obtained.

About This Manual

This manual is designed to allow integration of the Digital Wireless Corporation WIT2410 OEM

module into complete products. Care has been taken to try and make sure all of the information

in this manual is accurate. However, specifications can change over time and Digital Wireless

cannot guarantee the accuracy of this information. If you have any questions on any information

in this manual, please contact Digital Wireless Technical Support at (770) 564-5540.

TABLE OF CONTENTS

1. INTRODUCTION..................................................................................................................................1

1.1 Why Spread Spectrum?.....................................................................................................................1

1.2 Frequency Hopping vs. Direct Sequence.........................................................................................2

2. RADIO OPERATION............................................................................................................................4

2.1. Synchronization and Registration ...................................................................................................4

2.2. Data Transmission...........................................................................................................................5

2.2.1. Point-to-Point ........................................................................................................................5

2.2.2. Point-to-Multipoint................................................................................................................6

2.2.3. TDMA Mode.........................................................................................................................6

2.2.4. CSMA Mode .........................................................................................................................8

2.2.5. Full Duplex Communication.................................................................................................8

2.2.6. Error-free Packet Transmission Using ARQ.........................................................................8

2.3. Modes of Operation.........................................................................................................................9

2.3.1. Control and Data Modes........................................................................................................9

2.3.2. Sleep Mode..........................................................................................................................10

2.3.3. Low Power Mode and Duty Cycling...................................................................................10

3. PROTOCOL MODES..........................................................................................................................11

3.1. Packet Formats..............................................................................................................................12

3.1.1. Data Packet..........................................................................................................................13

3.1.3. Connect Packet....................................................................................................................13

3.1.4. Disconnect Packet (base only, receive only)......................................................................13

4. MODEM INTERFACE........................................................................................................................14

4.1. Interfacing to 5 Volt Systems........................................................................................................15

5. MODEM COMMANDS......................................................................................................................16

5.1. Serial Commands ..........................................................................................................................16

5.2. Network Commands......................................................................................................................17

5.3. Protocol Commands......................................................................................................................19

5.4. Status Commands..........................................................................................................................21

5.5. Memory Commands......................................................................................................................22

5.6. Modem Command Summary........................................................................................................23

6. WIT2410 DEVELOPER’S KIT...........................................................................................................24

6.1. COM24..........................................................................................................................................24

6.2. Demonstration Procedure..............................................................................................................25

6.3. Troubleshooting ............................................................................................................................26

7. APPENDICES......................................................................................................................................28

7.1. Technical Specifications ...............................................................................................................28

7.1.1. Power Specifications ...........................................................................................................28

7.1.2. RF Specifications.................................................................................................................28

7.2.2. Mechanical Specifications...................................................................................................28

7.3. Serial Connector Pinouts...............................................................................................................29

7.4. Approved Antennas.......................................................................................................................29

7.5. Technical Support .........................................................................................................................29

7.6. Mechanical Drawing .....................................................................................................................30

7.7. Warranty........................................................................................................................................31

1. INTRODUCTION

The WIT2410 radio transceiver provides reliable wireless connectivity for either

point-to-point or multipoint applications. Frequency hopping spread spectrum technology

ensures maximum resistance to noise and multipath fading and robustness in the presence of

interfering signals, while operation in the 2.4 GHz ISM band allows license-free use and

worldwide compliance. A simple serial interface supports asynchronous data up to 230400

bps. An on-board 3 KB buffer and an error-correcting over-the-air protocol provide smooth

data flow and simplify the task of integration with existing applications.

- Multipath fading impervious

frequency hopping technology

with 75 frequency channels

(2401-2475 MHz).

- Supports point-to-point or

multipoint applications.

- Meets FCC rules 15.247 and ETS

300.328 for worldwide license-

free operation.

- Superior range to 802.11 wireless

LAN devices.

- Transparent ARQ protocol

w/3KB buffer ensures data

integrity.

- Digital addressing supports up to

32 networks, with 62 remotes per

network.

- Low power 3.3v CMOS signals

- Simple serial interface handles both

data and control at up to 230400

bps.

- Fast acquisition typically locks to

hopping pattern in 5 seconds or less.

- Selectable 10 mW or 100 mW

transmit power.

- Support for diversity antenna.

- Built-in data scrambling reduces

possibility of eavesdropping.

- Nonvolatile memory stores

configuration when powered off.

- Smart power management features

for low current consumption.

- Dynamic TDMA slot assignment

that maximizes throughput.

1.1 Why Spread Spectrum?

The radio transmission channel is very hostile, corrupted by noise, path loss and

interfering transmissions from other radios. Even in a pure interference-free

environment, radio performance faces serious degradation through a phenomenon

known as multipath fading. Multipath fading results when two or more reflected rays of

the transmitted signal arrive at the receiving antenna with opposing phase, thereby

partially or completely canceling the desired signal. This is a problem particularly

prevalent in indoor installations. In the frequency domain, a multipath fade can be

described as a frequency-selective notch that shifts in location and intensity over time as

reflections change due to motion of the radio or objects within its range. At any given

time, multipath fades will typically occupy 1% - 2% of the 2.4 GHz band. This means

that from a probabilistic viewpoint, a conventional radio system faces a 1% - 2% chance

of signal impairment at any given time due to multipath.

Spread spectrum reduces the vulnerability of a radio system to both interference from

jammers and multipath fading by distributing the transmitted signal over a larger region

of the frequency band than would otherwise be necessary to send the information. This

allows the signal to be reconstructed even though part of it may be lost or corrupted in

transit.

Figure 1

Narrowband vs. spread spectrum in the presence of interference

1.2 Frequency Hopping vs. Direct Sequence

The two primary approaches to spread spectrum are direct sequence (DS) and frequency

hopping (FH), either of which can generally be adapted to a given application. Direct

sequence spread spectrum is produced by multiplying the transmitted data stream by a

much faster, noise-like repeating pattern. The ratio by which this modulating pattern

exceeds the bit rate of the baseband data is called the processing gain, and is equal to the

amount of rejection the system affords against narrowband interference from multipath

and jammers. Transmitting the data signal as usual, but varying the carrier frequency

rapidly according to a pseudo-random pattern over a broad range of channels produces a

frequency hopping spectrum system.

Figure 2

Forms of spread spectrum

One disadvantage of direct sequence systems is that due to spectrum constraints and the

design difficulties of broadband receivers, they generally employ only a minimal amount

of spreading (typically no more than the minimum required by the regulating agencies).

For this reason, the ability of DS systems to overcome fading and in-band jammers is

relatively weak. By contrast, FH systems are capable of probing the entire band if

necessary to find a channel free of interference. Essentially, this means that a FH

system will degrade gracefully as the channel gets noisier while a DS system may

exhibit uneven coverage or work well until a certain point and then give out completely.

Because it offers greater immunity to interfering signals, FH is often the preferred

choice for co-located systems. Since direct sequence signals are very wide, they tend to

offer few non-overlapping channels, whereas multiple hoppers may interleave with less

interference. Frequency hopping does carry some disadvantage in that as the transmitter

cycles through the hopping pattern it is nearly certain to visit a few blocked channels

where no data can be sent. If these channels are the same from trip to trip, they can be

memorized and avoided; unfortunately, this is generally not the case, as it may take

several seconds to completely cover the hop sequence during which time the multipath

delay profile may have changed substantially. To ensure seamless operation throughout

these outages, a hopping radio must be capable of buffering its data until a clear channel

can be found. A second consideration of frequency hopping systems is that they require

an initial acquisition period during which the receiver must lock on to the moving carrier

of the transmitter before any data can be sent, which typically takes several seconds. In

summary, frequency hopping systems generally feature greater coverage and channel

utilization than comparable direct sequence systems. Of course, other implementation

factors such as size, cost, power consumption and ease of implementation must also be

considered before a final radio design choice can be made.

As an additional benefit, RF spectrum has been set aside at 2.4 GHz in most countries

(including the U.S.) for the purpose of allowing compliant spread spectrum systems to

operate freely without the requirement of a site license. This regulatory convenience

alone has been a large motivation for the industry-wide move toward spread spectrum.

2. RADIO OPERATION

2.1. Synchronization and Registration

As discussed above, frequency hopping radios periodically change the frequency at which

they transmit. In order for the other radios in the network to receive the transmission, they

must be listening to the frequency over which the current transmission is being sent. To do

this, all the radios in the net must be synchronized and must be set to the same hopping

pattern. All radios in a net must be set to the same hopping pattern before attempting to

communicate.

In point-to-point or point-to-multipoint arrangements, one radio module is designated as the

base station. All other radios are designated remotes. One of the responsibilities of the base

station is to transmit a synchronization signal to the remotes to allow them to synchronize

with the base station. Since the remotes know the hopping pattern, once they are

synchronized with the base station, they know which frequency to hop to and when. Every

time the base station hops to a different frequency, it immediately transmits a synchronizing

signal.

When a remote is powered on, it rapidly scans the frequency band for the synchronizing

signal. Since the base station is transmitting over 75 frequencies and the remote is scanning

75 frequencies, it can take several seconds for a remote to synch up with the base station.

Once a remote has synchronized with the base station, it must request registration from the

base station. The registration process identifies to the base station the remotes from which

transmissions will be received and not discarded. Registration also allows tracking of

remotes entering and leaving the network. The base station builds a table of serial numbers

of registered remotes. To improve efficiency, the 24-bit remote serial number is assigned a

6-bit “handle” number. Two of these are reserved for system use, thus each base station can

necessary, the automatic handle assignment can be overridden to explicitly tie certain handles

to certain remotes. See the section on Network Commands for details on the Set Default

Handle command.

To detect if a remote has gone offline or out of range, the registration must be “renewed”

once every 256 hops. Registration is completely automatic and requires no user application

intervention. When the remote is registered, it will receive several network parameters from

the base. This allows the base to automatically update these network parameters in the

remotes over the air. Once a parameter has been changed in the base, it is automatically

changed in the remotes. The parameters automatically changed are hop duration, the duty

cycle and the multiple access mode, i.e., TDMA or CSMA.

At the beginning of each hop, the base station transmits a synchronizing signal. After the

synchronizing signal has been sent, the base will transmit any data in its buffer unless packet

transmit delay has been set. The packet transmit delay parameter allows for the transmission

of groups of continuous data in transparent mode (protocol mode 0). In TDMA mode the

amount of data that the base station can transmit per hop is determined by the hop duration

and the number of remotes registered with the base. In CSMA mode, the maximum amount

of data sent is determined by maximum data length. In any event, the maximum amount of

data sent by a base station or remote per hop is 127 bytes. If there is no data to be sent, the

base station will not transmit until the next frequency.

The operation of the remotes depends on whether the remote is set up for TDMA mode or

CSMA mode. In TDMA mode, the operation of the remotes is the same as the base station

without the synchronization signal.

In CSMA mode, remotes compete on an ad hoc basis for transmission time. The likelihood

that a remote with will attempt to transmit immediately is affected by the persistence

parameter. If a collision is detected with another radio, the remote will wait a random period

of time before trying to retransmit. The backoff parameter controls the maximum time a

remote will wait before attempting to retransmit. Unregistered remotes can request

registration any time after the base station transmission. Refer to the section Protocol

Commands for details on the persistence and backoff parameters.

Except for the registration process which occurs only when a remote logs onto the network,

the whole procedure is repeated on every frequency hop. Refer to the section on Modem

Commands for complete details on parameters affecting the transmission of data.

2.2. Data Transmission

The WIT2410 supports two network configurations: point-to-point and point-to-multipoint.

In a point-to-point network, one radio is set up as the base station and the other radio is set up

as a remote. In a point-to-multipoint network, a star topology is used with the radio set up as

a base station acting as the central communications point and all other radios in the network

set up as remotes. In this configuration, all communications take place between the base

station and any one of the remotes. Remotes cannot communicate directly with each other.

It should be noted that point-to-point mode is a subset of point-to-multipoint mode and

therefore there is no need to specify one mode or the other.

2.2.1. Point-to-Point

In point-to-point mode, unless packet transmit delay has been set, the base station will

transmit whatever data is in its buffer limited to 127 bytes or by the length of the base slot

size. If the base station has more data than can be sent on one hop, the remaining data will be

sent on subsequent hops. In addition to the data, the base station adds some information to

the transmission over the RF link. It adds the address of the remote to which it is

transmitting, even though in a point-to-point mode there is only one remote. It also adds a

sequence number to identify the transmission to the remote. This is needed in the case of

acknowledging successful packets and retransmitting errored packets. Also added is a 24-bit

CRC to allow the base to check the received transmission for errors. When the remote

receives the transmission, it will acknowledge the transmission if it was received without

errors. If no acknowledgment is received, the base station will retransmit the same packet on

the next frequency hop.

In point-to-point mode, a remote will transmit whatever data is in its buffer up to the limit of

its maximum packet length. If desired, a minimum packet length can also be set, which forces

the remote to wait until a certain amount of data is available or the specified packet transmit

delay is exceeded before transmitting. If the remote has more data than can be sent on one

hop, it will send as much data as possible as a packet, adding its own address, a packet

sequence number and 24-bit CRC. These additional bytes are transparent to the user

application if the protocol mode is 00 (which is the default). In the event a remote has more

data to send, the data will be sent on subsequent hops. If the packet is received by the base

station without errors, the base station will acknowledge the packet. If the remote does not

receive an acknowledgment, it will retransmit the packet on the next frequency hop. To the

user application, acknowledgments and retransmissions all take place behind the scenes

without the need for user intervention.

2.2.2. Point-to-Multipoint

In point-to-multipoint mode, data sent from the user application to the base station must be

packetized by the user application. This is necessary to identify the remote to which the base

station should send data. When the user packet is received by the remote, if the remote is in

transparent mode (protocol mode 0), the packetization bytes are stripped by the remote. In

this instance the remote host receives just data. If the remote is not in transparent mode, the

remote host will receive the appropriate packet header as specified by the remote’s protocol

mode. Refer to the section Protocol Modes for details on the various packet formats.

When a remote sends data to a base station in point-to-multipoint mode, the remote host does

not need to perform any packetization of the data. The remote will add address, sequence

and CRC bytes as in the point-to-point mode. When the base station receives the data, the

base station will add packetization header bytes according to its protocol mode setting.

2.2.3. TDMA Mode

For applications needing guaranteed bandwidth availability, the TDMA mode of the

WIT2410 can meet this requirement. This is the default mode of the WIT2410. In TDMA

mode, each remote has an assigned time slot during which it can transmit. The base station

time slot is set independently of the remote time slots through the Set Base Slot Size

command. The base station assigns each remote a time slot and informs the remotes of the

size of the time slot. All remote time slots are the same size which is determined by the

number of remotes registered with the base station. The slot size is a dynamic variable that

changes as the number of registered remotes changes. The remotes are continually updated

with the time slot size. This approach continually maximizes the data throughput. The base

station divides the amount of time available per hop by the number of registered remotes up

to a maximum of 16 times slots per hop. If the number of registered remotes is greater than

16, the time slots will be spread across the required number of hops. For networks with more

than 16 possible remotes, the Set Duty Cycle command must be used to specify a duty cycle -

- the number of hops over which the time slots must be spread. For 1 to 16 remotes, no duty

cycle is required; for 17 to 32 remotes a duty cycle of at least ½ is required; and for 33 to 62

remotes a duty cycle of ¼ or more is necessary. An added benefit of using the power save

mode to set a duty cycle is improved average current consumption efficiency. Refer to the

Status Commands section for details of this command.

When setting up a TDMA network, keep in mind that time slot length, maximum packet size

and hop duration are all interrelated. The hop duration parameter will determine the time

slot size and the maximum amount of data that can be transmitted per hop by the remotes.

There is a hard limit of the absolute maximum amount of data that can be sent on any given

hop of 212 bytes regardless of any parameters. The base station requires 1.7 ms overhead for

tuning, the synchronization signal and parameter updating, as well as a guard time of 500 us

between each remote slot. Thus the amount of time allocated per remote slot is roughly:

hop duration – base slot – 1.7ms - ( # of registered remotes-1)·500us

( # of registered remotes)

Take for example a network comprised of a base station and 10 remotes. A hop duration of

15 ms is chosen. We decide that the base station needs to be able to send up to 32 bytes each

hop (equivalent to a capacity for the base of ~ 21 kbps). Counting the 1.7 ms overhead for

the base packet and making use of the fact that our RF rate is 460.8 kbps, we determine that

the base slot requires approximately:

Each remote time slot will be:

15 ms – 2.3 ms – (9)·0.5 ms

From our RF data rate of 460.8kbps we see that it takes 17.36 µs to send a byte of data, so

each remote will be able to send up to

= 47 bytes of data per hop.

Note that the 47 bytes is the actual number of data bytes that can be sent. If the WIT2410 is

using a protocol mode, the packet overhead does not need to be considered. So in this

example, the total capacity per remote would be:

If we figure a minimum margin of safety for lost packets and retransmissions of about 20%,

we see that this would be more than sufficient to support 19.2 kbps of continuous data per

remote. It is also useful to remember that the asynchronous data input to the WIT2410 is

= 0.82 ms

0.82 ms

17.36

32·8

460.8kbps+ 1.7 ms = 2.3 ms

47 bytes

15 ms = 25 kbps

stripped of its start and stop bits during transmission by the radio, yielding a "bonus" of 10/8

or 25% in additional capacity.

The above calculations are provided as a means of estimating the capacity of a multipoint

WIT2410 network. To determine the precise amount of capacity, you can actually set up the

radio system and then query the maximum packet length from one of the remotes in control

mode to discover its exact setting. Divide this number by the hop duration as above to get

the remote's exact capacity.

2.2.4. CSMA Mode

CSMA mode is not currently available for the WIT2410.

2.2.5. Full Duplex Communication

From an application perspective, the WIT2410 communicates in full duplex. That is, both

the user application and the remote terminal can be transmitting data without waiting for the

other to finish. At the radio level, the base station and remotes do not actually transmit at the

same time. If they did, the transmissions would collide. As discussed earlier, the base

station transmits a synchronization signal at the beginning of each hop followed by up to

three packets of data. After the base station transmission, the remotes will transmit. Each

base station and remote transmission may be just part of a complete transmission from the

user application or the remote terminal. Thus, from an application perspective, the radios are

communicating in full duplex mode since the base station will receive data from a remote

before completing a transmission to the remote.

2.2.6. Error-free Packet Transmission Using ARQ

The radio medium is a hostile environment for data transmission. In a typical office or

factory environment, 1% - 2% of the 2.4 GHz frequency band may be unusable at any given

time at any given station due to noise, interference or multipath fading. For narrowband

radio systems (and also many spread spectrum radio systems which use direct sequence

spreading), this would imply a loss of contact on average of over 30 seconds per hour per

station. The WIT2410 overcomes this problem by hopping rapidly throughout the band in a

pseudo-random pattern. If a message fails to get through on a particular channel, the

WIT2410 simply tries again on the next channel. Even if two thirds of the band are

unusable, the WIT2410 can still communicate reliably.

Data input to the WIT2410 is broken up by the radio into packets. A 24-bit checksum is

attached to each packet to verify that it was correctly received. If the packet is received

correctly, the receiving station sends an acknowledgment, or ACK, back to the transmitting

station. If the transmitter doesn't receive an ACK, at the next frequency hop it will attempt to

send the packet again. When ARQ is enabled, the transmitting radio will attempt to send a

packet packet attempts limit times before discarding the packet. A value of 00H disables

ARQ. When it is disabled, it is the responsibility of the user application to track errored or

missing packets. A second parameter, ARQ Mode, allows the choice between using ARQ to

resend errored packets or always sending a packet packet attempts limit times regardless of

the success or failure of any given transmission.

All of this error detection and correction is transparent to the user application. All the user

application sees is non-errored data from the modem. However, if the ARQ mode is

disabled, error detection and correction will be the responsibility of the user application.

Refer to the Protocol Commands section for complete details.

2.3. Modes of Operation

2.3.1. Control and Data Modes

The WIT2410 has two modes of operation: Control mode and Data mode. When in Control

Mode, the various radio and modem parameters can be modified. When in Data Mode, only

data can be transmitted. The default mode is Data Mode. There are two ways to enter

Control Mode. The first way is to assert the Configure (CFG) pin on the modem. Upon

entering Control Mode, the modem will respond with a > prompt. After each command is

entered, the modem will again respond with a > prompt. As long as the CFG pin is asserted,

data sent to the modem will be interpreted as command data. Once the CFG pin is

deasserted, the modem will return to Data Mode.

The second method for entering Control Mode is to send the escape sequence :wit2410 (all

lower case) followed by a carriage return. In the default mode, the escape sequence is only

valid immediately after power up or after deassertion of the Sleep pin on the modem. The

modem will respond in the same way with a > prompt. To return to Data Mode, enter the

Exit Modem Control Mode command, z>, or assert and deassert the Sleep pin. There are

three modes for the escape sequence, controlled by the Set Escape Sequence Mode comand,

zc:

zc=0 Escape sequence disabled

zc=1 Escape sequence available once at startup (default setting)

zc=2 Escape sequence available at any time

The zc2 mode setting is useful if the user application has a need to change the modem

settings "on the fly". In this mode the escape sequence is always and may be sent at any time

after a pause of at least 20ms. The modem will respond in the same way as when in the

default mode. It is necessary to issue the Exit Modem Control Mode command, z>, before

resuming data transmission. The escape sequence must be interpreted as data until the last

character is received and as such may be transmitted by the modem to any listening modems.

2.3.2. Sleep Mode

To save power consumption for intermittent transmit applications, the WIT2410 supports a

Sleep Mode. Sleep Mode is entered by asserting the Sleep pin on the modem interface.

While in Sleep Mode, the modem consumes less than 50µA. This mode allows the radio to

be powered off while the terminal device remains powered. After leaving Sleep Mode, the

radio must re-synchronize with the base station and re-register.

2.3.3. Low Power Mode and Duty Cycling

To conserve power, WIT2410 remotes power down the receiver and transmitter between

hops when not in use. Base stations must remain active all the time to handle any

transmission from any remote. Remotes can save even more power by enabling the duty

cycle feature. This feature causes a remote to power down for 2N frequency hops where 1/2N

is the duty cycle. Rather than attempting to transmit on every frequency hop when data is in

the transmit buffer, a remote will attempt to transmit only every 2N hops. Roughly speaking,

this will proportionately reduce the average power consumption while increasing average

latency. When there are more than 16 remotes being operated in TDMA mode, duty cycling

must be enabled since a maximum of 16 time slots are available per hop.

3. PROTOCOL MODES

In point-to-point applications, it is generally desired that the radios operate in a transparent

mode. That is, raw unformatted data is sent from the host to the radio and is received as raw

data from the receiving end. The addressing and error detection and correction is still

performed by the radios, but it is transparent to the user application. To set up a point-to-

point network, one radio has to be set up as a base station. When the radios are powered on,

the base station will send out the synchronization signal at the beginning of each hop. The

remote will synchronize with the base and automatically request registration. Once the

remote is registered, the radios can transmit data. Protocol mode operation is available in

point-to-point mode if desired.

In point-to-multipoint mode, the data sent to the base station by the user application must

adhere to a packet format. This allows transmissions from the base station to be directed to a

specific remote. Data received by a base station from a remote is similarly formatted to

identify to the user application the remote that sent the transmission. The remotes may still

use transparent mode without formatting to send data to the base, if desired. The WIT2410

supports 12 protocol formats which are described in detail below. The protocol format is

selected through the Set Protocol Mode command.

mode 00 Transparent mode used for point-to-point networks or

multipoint remotes; does not support any packet types.

mode 01 This is the simplest protocol mode supporting Data and

Command packets only. No CONNECT or

DISCONNECT packets are supported and no sequence

numbers are provided.

packet types supported: Data

mode 02 This mode includes notification when remotes are

registered or dropped through CONNECT and

DISCONNECT packets that are sent to the user

application at the base station and at the remote. No

sequence numbers are provided.

packet types supported: Data

CONNECT

DISCONNECT

mode 04 This is the packet format used by the WIT2400. This

allows legacy software to operate the WIT2410. Note

however, that since different air data rates are used,

WIT2410s and WIT2400s cannot be mixed in a

network.

packet types supported: 2400 data format

(addresses must be limited to 0..62)

modes 05 – 08 reserved for future use.

mode 09 This mode sends the protocol mode 01 packets during

transmit but receives data transparently.

mode 0A This mode sends the protocol mode 02 packets during

transmit but receives data transparently.

mode 0C This mode sends the protocol mode 04 packet during

transmit but receives data transparently.

modes 0D – 0F reserved for future use.

mode 11 This mode sends data transparently but supports

protocol mode 1 during reception.

mode 12 This mode sends data transparently but supports

protocol mode 2 during reception.

mode 14 This mode sends data transparently but supports

protocol mode 4 during reception.

3.1. Packet Formats

The byte formats for each packet type are shown in the table below. Packet fields are

organized to fall on byte boundaries. In the case of bit-level fields, most-significant bits are

on the left.

WIT2400 packet type (mode 04):

DATA 0000 0010 00HH HHHH 0LLL LLLL <0-127 bytes data> 0000 0011

MRTP (WIT2410) packet types (modes 01-03):

Transmit and Receive:

DATA 1110 1001 00HH HHHH 0LLL LLLL <0-127 bytes data>

Receive only:

CONNECT 1110 1001 10HH HHHH RRRR TTTT 00NN NNNN <3 byte remote ID>

DISCONNECT 1110 1001 11HH HHHH 0111 1111

H: handle number (0-63)

L : data length (0-127)

N: remote's previous network number (if roamed)

R: receive sequence number (from previous cell)

T: transmit sequence number (from previous cell)

3.1.1. Data Packet

Modes 01 & 02: 1110 1001 00HH HHHH 0LLL LLLL <0-127 bytes data>

Mode 04 (WIT2400): 0000 0010 00HH HHHH 0LLL LLLL <0-127 bytes data> 0000 0011

H: handle number (0-63)

L : data length (0-127)

This packet carries user data. The handle number is the handle of the sending or receiving

remote, depending on whether the data is going to or coming from the base. Up to 127 bytes

of user data may be carried per data packet.

Handle 63 is reserved for broadcast packets from the base to all remotes. Acknowledgment

requests are not supported for broadcasts. For this reason, it is a good idea to send broadcast

messages several times to increase the odds of reaching all remotes.

3.1.3. Connect Packet

1110 1001 10HH HHHH RRRR TTTT 00NN NNNN <3-byte remote ID> (base, receive only)

H: handle number (0-62)

R: receive sequence number (from previous cell)

T: transmit sequence number (from previous cell)

N: network number of the previous base (if roamed)

1110 1001 10HH HHHH RRRR TTTT 00NN NNNN <3-byte base ID> (remote, receive only)

H: handle number (0-62)

R: receive sequence number

T: transmit sequence number

N: network number of base

Remotes must go through an automatic registration process when roaming from one base to

another, after loss of contact, or when acquiring a base signal for the first time after power

up. The base then assigns the remote a handle value, may or may not assign it a dedicated

time slice depending on the user settings, and notifies the user application of the new remote

with a connect packet.

The network number of the last base the remote was connected to is given to aid user

software in resending orphan packets that may have been sent to the remote's previous cell.

If the remote has been powered up for the first time and this is the first base contacted, the

last base ID will be reported as FFH.

3.1.4. Disconnect Packet (base only, receive only)

1110 1001 10HH HHHH 0111 1111

H: handle number (1-62)

When a remote goes out of range or roams to another cell, the base issues a disconnect packet

to indicate that the remote is no longer available.

4. MODEM INTERFACE

Electrical connection to the WIT2410 is made through a 16-pin male header on the modem

module. The signals are 3.3 volt signals and form an RS-232 style asynchronous serial

interface. The table below provides the connector pinout.

Pin Signal Type Description

1 GND - Signal and chassis ground

2 TXD Input Transmit data. Input for serial data to be transmitted. In Control

Mode also used to transmit modem commands to the modem.

3 RXD Output Receive data. Output for received serial data. In Control Mode, also

carries receive modem status from the modem.

4 Input Configuration selector. Used to switch between Control and Data

Modes. Normally, CFG will be set for Data Mode. An internal 10K

pull-up enables Data Mode if this signal is left unconnected. Control

Mode is also accessible by transmitting an escape sequence

immediately after wake up or power up.

(0v) 1 = Control Mode

(3.3v) 0 = Data Mode

5 Input Request to send. Gates the flow of receive data from the radio to

the user on or off. In normal operation this signal should be

asserted. When negated, the WIT2410 buffers receive data until

RTS is asserted.

(0v) 1 = Receive data (RxD) enabled

(3.3v) 0 = Receive data (RxD) disabled.

6SLEEP Input Sleeps/wakes radio transceiver. In sleep mode all radio functions

are disabled consuming less than 50µA. At wake up, any user

programmed configuration settings are refreshed from non-volatile

memory, clearing any temporary settings that may have been set.

(3.3v) 1 = Sleep Radio

(0v) 0 = Wake Radio

7 Output Data carrier detect. For remotes, indicates the remote has

successfully acquired the hopping pattern of the base station.

(0v) 1 = Carrier detected (synchronized)

(3.3v) 0 = No carrier detected (not synchronized)

8 Output Clear to send. Used to control transmit flow from the user to the

radio.

(0v) 1 = Transmit buffer not full, continue transmitting

(3.3v) 0 = Transmit buffer full, stop transmitting

9-15 - - Reserved for future use. Do not connect.

16 VCC - Positive supply. Min 3.3 v, 5.0 v nominal, 10.0 v max.

RTS

DCD

CTS

CFG

4.1. Interfacing to 5 Volt Systems

The modem interface signals on the WIT2410 are 3.3 volt signals. To interface to 5 volt

signals, the resistor divider network shown below must be placed between the 5 volt signal

outputs and the WIT2410 signal inputs. The output voltage swing of the WIT2410 3.3 volt

signals is sufficient to drive 5 volt logic inputs.

10 kΩ

15 kΩ

From 5v

Output To 3.3v Input

5. MODEM COMMANDS

The WIT2410 is configured and controlled through a series of commands. These commands

are sent to the modem directly when the modem is in Control Mode or through Command

Packets when the modem is in Data Mode. The command syntax is the same for either

method, a one- or two-letter command followed by one or more parameters. The modem

will respond with a two-byte message that indicates the new modem parameter value. The

commands are loosely grouped into five different categories: Serial commands, Network

commands, Protocol commands, Status commands and Memory commands. Each command

is described in detail below. In the descriptions, brackets ([,]) are used to denote a set of

optional arguments. Vertical slashes (|) separate selections. For example, given the string

wn[?|0..3f], some legal commands are wn?, wn0, wn3 and wna. Most commands which set

a parameter also have a ? option which causes the modem to respond with the current

parameter setting, e.g., wn?

5.1. Serial Commands

These commands affect the serial interface between the modem and the host. The default

settings are 9600 bps and protocol mode 0.

Command Description

sd[?|00..FF] Set Data Rate Divisor

Data Rate Divisor (hex)

1200 bps = BF

2400 bps = 5F

9600 bps = 17

14400 bps = 0F

19200 bps = 0B

28800 bps = 07

38400 bps = 05

57600 bps = 03

115200 bps = 01

230400 bps =00

sp[?|00..14] Set Protocol Mode

00 = point-to-point transparent mode

01 = basic command and data only

02 = command, data and connection notification

04 =

WIT2400 protocol mode

05 – 08 =reserved for future use

09 = mode 01 during transmit, transparent receive

0A = mode 02 during transmit, transparent receive

0C = mode 04 during transmit, transparent receive

0D – 10 =reserved for future use

11 = transparent transmit, mode 01 during receive

12 = transparent transmit, mode 02 during receive

14 = transparent transmit, mode 04 during receive

Set Data Rate Divisor

Sets the serial bit rate between the modem and the host. This command takes effect

immediately and will require adjusting the host serial rate to agree. Nonstandard rates may

be programmed by entering a data rate divisor computed with the following formula:

DIVISOR = (230400/RATE)-1

Round all non-integer values down.

Set Protocol Mode

Enables the base station to operate in a multipoint network. Depending on the user

application, more or less acknowledgment may be desired by the application. Remotes can

operate in transparent mode even though the base station is operating in one of the

nontransparent modes.

When using a protocol mode, make sure to count in packet overhead when calculating

network performance. Refer to the section on Protocol Modes for details on each format.

5.2. Network Commands

Network commands are used to set up a WIT2410 network and to set radio addressing and

configuration.

Command Description

wb[?|0|1] Set Transceiver Mode

0 = remote (default)

1 = base station

wd[?|0-3f] Set Default Handle

Used to override automatic handle assignment by the base station

30 = default

wg[?|0|1] Enable Global Network Mode

0 = Link only to hop pattern specified by wn parameter (default)

1 =Link to any hop pattern, regardless of wn parameter

wn[?|0-1f] Set Hopping Pattern (Network Number)

0 = default

wp[?|0|1] Set Transmit Power

0 = 10mW

1 = 100mW (default)

wr? Read Receive Signal Strength

Set Transceiver Mode

Sets modem operation as either base station or remote. Default is remote.

Set Default Handle

Sets handle number between 1 and 62 inclusive for a remote. This handle will override the

automatic handle assignment by the base station. This command can be used in applications

where it is desired to have specific modems have specific handles.

When specified for the base, the default handle determines which remote it will address when

transparent protocol mode is in effect.

Enable Global Network Mode

For networks with multiple base stations, remotes are ordinarily only able to link to one base

station, set by the hopping pattern. Enable the global mode if you wish to allow remotes to

link to any base station it can hear, acquiring whatever hop pattern is required.

Set Hopping Pattern

The WIT2410 has 32 preprogrammed hopping patterns (also referred to as network

numbers). By using different hopping patterns, nearby or co-located networks can avoid

interfering with each other’s transmissions. Even if both networks tried to use the same

frequency, on the next hop they would be at different frequencies.

Set Transmit Power

The WIT2410 has two preset transmit power levels, 10mW (10dBm) and 100mW (20dBm).

Control of the transmit power is provided through this command. Default is 100mW.

Read Receive Signal Strength Indicator (RSSI)

This command reports the relative signal strength averaged over the last 10 hops. This

command returns a two-digit hexadecimal value and can range from 00 to FF. This is

available only at the remotes as the base station is the only source that transmits on a regular

basis. Plus, in a point-to-multipoint network the base will receive a different signal strength

from each remote.

5.3. Protocol Commands

These commands can be used to tune the transceiver for optimum transmission of data across

the RF link. For most applications, the default values are adequate.

Command Description

pe[?|0-3] Set Alternative Frequency Band

0 = FCC operation. (default)

1 = France (ETSI)

2 = Spain

3 = Japan

ph[?|00-ff] (base only) Set Hop Duration

90H = default

pk[?|00-d0] Set Minimum Data Length

0 = default

pl? Get Maximum Data Length

D4 = default

pr[?|00-ff] Set Packet Attempts Limit

10H = default

pt[?|00-ff] Set Packet Transmit Delay

00H = default

pw[?|00-30] (base only) Set Base Slot Size

04H = default

px[?|0|1] Set ARQ mode.

0 = ARQ enabled (default)

1 = ARQ disabled (redundant transmission)

Note: Incorrect setting of these parameters may result in reduced throughput or loss of data packets.

Set Alternative Frequency Band

When set to 1, limits the operating RF channel set to the 2448 to 2480 MHz frequency band

for compliance with European ETSI or French regulatory standards. When set to 2, sets

appropriate operation for Spain. When set to 3, sets appropriate operation for Japan. This

setting should be set to 0, for FCC-compliant operation in the US (this is the default).

Set Hop Duration

Sets the length of time the transceiver spends on each frequency channel. A smaller value

will allow the remote to lock on to the base signal faster at system startup, and will generally

decrease packet latency. A larger value increases network capacity, due to decreased

overhead in channel switching. The hop duration is specified in 69.4µs increments. The

default value of 90H corresponds to a duration of 10ms. The maximum value of FFH is

17.7ms. For best results, do not specify a duration of less than 3 ms. This value only needs

to be set in the base which broadcasts the parameter to all remotes. However, link time can

be reduced if this value is also programmed into the remotes, which use it as a starting value

when scanning for the base.

Get Maximum Data Length (read only)

This parameter indicates the largest number of bytes that a remote will transmit per hop,

based on the size of the slot it has been allocated by the base. In general more remotes mean

less data can be transmitted per remote. By reading this parameter and dividing by the hop

duration, the remote's data rate capacity can be determined.

Set Minimum Data Length

This sets the minimum threshold number of bytes required to form a packet in transparent

mode. The radio will wait until the packet transmit delay elapses before sending a data

packet with less than this number of bytes. Can be used to keep short, intermittent

transmissions contiguous.

Set Packet Attempts Limit

Sets the number of times the radio will attempt to send an errored packet before discarding it

if ARQ Mode is set to 0. If ARQ Mode is set to 1, it is the number of times every packet will

be sent, regardless of success or failure of a given attempt.

Set Packet Transmit Delay

When used in conjunction with the minimum data length parameter, this ets the amount of

time from the receipt of a first byte of data from the host until the radio will transmit in

transparent mode. Default is 00H which causes transmission to occur without any delay.

When a host is sending a group of data that needs to be sent together, setting this parameter

will provide time for the group of data to be sent by the host before the radio transmits. If the

length of data to be sent together is longer than the time slot can send, the data will not be

sent together but will be broken up over multiple hops. Incremented in 69.4µs steps with a

maximum value FFH or 17.7ms.

Set Base Slot Size (base station only)

Sets the amount of time allocated for transmission on each hop for the base station time slot

in 69.4µs increments, corresponding to 4 bytes per unit. Maximum value is 30H which

corresponds to 192 bytes.

Set ARQ Mode

Sets ARQ mode when set to 0 which is the default. In this mode the radio will resend an

errored packet until either successful or packet attempt limit attempts have been made. When

set to 1 selects redundant transmit mode that will send every packet packet attempt limit

times regardless of success or failure of any given attempt.

5.4. Status Commands

These commands deal with general interface aspects of the operation of the WIT2410.

Command Description

zb[?|0|1] Banner Display Disable

0 = disabled

1 = enabled (default)

zc[?|0..2] Set Escape Sequence Mode

0 = disabled

1 = once after reset (default)

2 = unlimited times

zh? Read factory serial number high byte.

zm? Read factory serial number middle byte.

zl? Read factory serial number low byte.

zp[?|0-5] Set the duty cycle at which the modem will wake up to send and receive data.

Duty cycle equals 1/2N where the argument of the command equals N.

z> Exit Modem Control Mode

Banner Display Disable

Enables or disables display of the banner string and revision code automatically at power-up.

May be disabled to avoid being mistaken for data by the host.

Set Escape Sequence Mode

Enables or disables the the ability to use the in-data-stream escape sequence method of

accessing Control Mode by transmitting the string ":wit2410". When this mode is set to 1,

the escape sequence only works immediately after reset (this is the default). When set to 2,

the escape sequence may be used at any time in the data stream when preceded by a pause of

20 ms. For backwards compatibility with the WIT2400, the string ":wit2410" is also

accepted for entering Control Mode. Note that the escape sequence must be interpreted as

data by the radio until the last character is received, and as such will be generally be

transmitted to a receiving radio station, if any.

Read Factory Serial Number High, Middle and Low Bytes.

These read only commands return one of the three bytes of the unique factory-set serial

number, which are also visible in the startup banner.

Set Duty Cycle

Allows reduced power consumption by having a remote wake up only every 2N hops to

receive and transmit. Power consumption is roughly proportional to the duty cycle selected.

For example, if N=2, the remote will wake up every fourth hop. Power consumption will be

roughly ¼ the consumption as when N=0. This parameter must be set to the appropriate

value when TDMA mode is being used with more than 16 remotes.

5.5. Memory Commands

The WIT2410 allows the user to store a configuration in nonvolatile memory, which is

loaded during the initialization period every time the radio is powered up.

Command Description

m0 Recall Factory Defaults

m< Recall Memory

m> Store Memory

Recall Factory Defaults

Resets the WIT2400 to its factory default state. This is useful for testing purposes or if there

is a problem in operation of the system and the configuration is suspect. Use the Store

Memory command afterwards if you wish the factory default settings to be remembered the

next time you cycle power or reset the radio.

Recall Memory

Useful for restoring the power-on settings after experimenting with temporary changes to

data rate, protocol or network parameters, etc.

Store Memory

This command is necessary after any command to change the data rate, transceiver address,

or other radio setting that you wish to make permanent.

5.6. Modem Command Summary

Serial Commands

sd[?|00..ff] Set Data Rate Divisor

sp[?|00..14] Set Protocol Mode

Network Commands

wb[?|0|1] Set Transceiver Mode

wd[?|0..3f] Set Default Handle

wn[?|00..3f] Set Hopping Pattern

wg[?|0|1] Enable Global Network Mode

wp[?|0|1] Set Transmit Power

wr? Read Receive Signal Strength (remote only)

Protocol Commands

pe[?|0..3] Set Alternative Frequency Band

ph[?|00..ff] Set Hop Duration (base only)

pl? Get Maximum Data Length

pk[?|00..d4] Set Minimum Data Length

pr[?|00..ff] Set Packet Attempts Limit

pt[?|00..ff] Set Packet Transmit Delay (remote only)

pw[?|00..20] Set Base Slot Size (base only)

px[?|0|1] Set ARQ Mode

Status Commands

zb[?|0|1] Banner Display Disable

zc[?|0..2] Set Escape Sequence Mode

zh? Read Factory Serial Number High Byte

zm? Read Factory Serial Number Middle Byte

zl? Read Factory Serial Number Low Byte

zp[?|0..4] Set Duty Cycle

z> Exit Modem Control Mode

Memory Commands

m0 Recall Factory Defaults

m< Recall Memory

m> Store Memory

Note: Brackets ([,]) as used here denote a set of optional arguments. Vertical slashes separate selections. For

example, given the string wn[?|00..3f], legal commands would be wn?,wn0, wn3, and wn2a. Most

commands which set a parameter also have a ? option which displays the current parameter setting; e.g., wn?.

6. WIT2410 DEVELOPER’S KIT

The WIT2410 Developer’s Kit contains two self-contained wireless modems built around the

WIT2410M OEM module. In addition, two WIT2410 OEM modules are included in the kit.

The self-contained units allow developers to get up and running quickly using standard RS-

232 interfaces without having to build a CMOS level serial interface. In addition, the self-

contained modems include status LEDs to provide modem status information visually. The

built-in battery pack allows the developer to use the modems without being tethered to a

power source. This provides a simple way to test the range of the radios. Other than the true

RS-232 signals of the serial interface, the self-contained modems operate exactly as the OEM

modules.

Connection is made to the modems through a standard DB-9 connector. The modems are set

up as DCE devices requiring the use of a straight-through cable to connect to DTE devices.

The pinout is provided in Section 7.3. The modems can be used with just a three wire

connection. Transmit data, receive data and ground are the three required connections. Note

that in this configuration, no flow control is available as the WIT2410 does not support

software flow control.

When the developer’s kit is shipped from the factory, one modem is set up as a base station

and the other is set up as a remote. The interface rate for both modems is set at 9600 bps.

The default setting for the network key allows the modems to communicate without changing

any settings. The modems are set up to operate in TDMA mode. As a quick test, separate

the two modems by about 5 feet, plug in the power and turn the modems on. Do not connect

the modems to any device. The Carrier Detect (CD) LED on the base station will come on

immediately. After a few seconds, the CD LED on the remote will come on. This indicates

that the modems have synchronized and have established a communications link.

An important point to remember is that if the base station is in Sleep mode, no

communications can take place until (1) the base station is taken out of sleep mode and (2)

the remote has synchronized with the base station. As the Sleep signal is brought out on the

pin usually occupied by DTR, connecting the base station to a PC serial port with DTR de-

asserted will put the modem into sleep mode. Some communications programs will attempt

to communicate immediately after asserting DTR. The base station will transmit this data,

but the remote will not be synchronized with the base station and will not receive the

transmission. In this instance, do not connect the Sleep signal to DTR of the serial port.

6.1. COM24

Provided with the developer’s kit is a simple communications program designed especially

for the WIT2410. This program provides a simple command interface to the modems along

with function key control for manipulating the serial port control lines and baud rates. This

program is designed to run under DOS although it will also work in the DOS box under most

versions of Windows. However, due to the limitations Windows puts on programs

interfacing directly to hardware, COM24 may not work under Windows 98 without booting

directly to DOS.

COM24 defaults to com1: and 9600 bps. The port and baud rate can be changed through the

invocation of the program. The invocation syntax is shown below:

COM24 <data rate> <port number>

Note that the data rate applies to the serial port of the computer. This parameter has no effect

on the modem. If the modem is set for 9600bps but COM24 is invoked to run at 19.2kbps,

the computer and the modem will be unable to communicate. When the modems are used for

the first time, if they are connected to serial port 1, the program can be invoked without data

rate or port number parameters.

The following function keys on the PC have the following functions in COM24:

F1 Toggles state of DTR (Sleep). State is shown in status line.

F2 Toggles state of RTS. State is shown in status line.

F3 Transmits “:wit2400”. Used to enter control mode.

F5 Toggles local echo. If you are transmitting characters through one modem to

another WIT2410, this allows you to see what you are typing.

F6 Toggles stream mode. Causes COM24 to transmit a repeating pattern of

characters. Useful for testing.

F8 Toggles binary mode. Displays extended ASCII and control characters.

Useful for testing.

PgUp Sets data rate of PC serial port to next higher value. Value is displayed in

status line. Useful when COM24 is used to change the WIT2410 interface

data rate. COM24 can communicate at new data rate without having to exit

and re-enter COM24.

PgDn Sets data rate of PC serial port to next lower value. Value is displayed in

status line.

The values of DTR (Sleep), RTS, DSR, CTS, DCD and the PC serial port rate are displayed

in the status line at the bottom of the display.

6.2. Demonstration Procedure

The procedure below provides a quick demonstration of the WIT2410.

1. Attach a transceiver to each computer, preferably between 5' and 30' apart for

convenience.

2. Start COM24 running on both computers by typing "COM24". If you are connected to a

serial port other than COM1:, use "COM24 9600 <port number>" to start the program;

e.g., for COM2:, use "COM24 9600 2". If you prefer, almost any other serial

communications program such as Procomm or QModem set for 9600 bps will also work.

3. Turn the radios on and use the function keys to set DTR and RTS to 1 (if you are using a

terminal program other than COM24, these are typically set automatically). The radio

should respond by setting both DSR and CTS to 1, and transmit a short sign-on message

including the firmware version and whether the unit is configured as a base or remote.

Watch the states of the hardware control lines on the status bar as you do this. The DCD

indicator should be lit on the base station. After a few seconds, the remote unit will

acquire the base station's signal and also assert its DCD signal.

4. Access modem control mode for each unit. To access modem control mode, use the F1

key to toggle DTR to 0 and back to 1 and then press the F3 key, which sends the

":wit2400" escape sequence. If you are not using COM24, simply turn the radio off and

back on and then type ":wit2400" (must be lower case, no backspace characters). The

transceiver should echo back “>” to indicate that you have entered modem control mode.

Check the remote unit's hopping pattern by entering "wn?" at the prompt. The remote

should respond with "0", the default setting. Check that the base station's hopping pattern

matches this by entering "wn?" at the base station.

5. Exit control mode by entering "z>". Do this for both radios. At this point, you should be

able to type characters into either radio and see them appear at the other side. If you are

using COM24, you can press the F6 key to transmit a repeating test pattern.

6. For a range test, disconnect the remote station from the computer and power supply. The

DCD indicator should remain lit as long as the base station is in range..

7. Exit COM24 by pressing the ESC key.

6.3. Troubleshooting

Radio is not responding.

Make sure DTR is asserted to bring the radio out of sleep mode. DSR should be on to

indicate the radio is ready.

Can’t enter modem control mode.

Make sure the host data rate is correct. The WIT2410 defaults to 9600 bps asynchronous.

Evaluation units do not have external access to the CFG_SEL signal; you must use the

:wit2410 power-on escape sequence to access modem control mode. The first characters

typed after the radio wakes up should be the escape sequence. Make sure you type the colon

(:) and enter the letters in lower case; the characters following the colon echo to show you

have typed them correctly. If using the “on-the-fly” escape sequence command, make sure a

pause of at least 20ms precedes the escape sequence.

Remote never detects carrier.

Check that the base station is running, and that the remote is programmed to the same

hopping pattern. Also check that the hop duration for base and remote are the same, and that

the remote has a non-zero link margin.

Carrier is detected, but no data appears to be received.

Make sure that RTS is asserted to enable receive character flow. In a point-to-point

application, if a remote is not receiving data, check that the base's deefault handle is the same

as the remote's. In a multipoint application, check that the remote is not configured for

protocol mode and that the base is using the correct protocol format and destination handle.

Radio is interfering with other nearby circuits.

It is possible for the RF energy envelope to be rectified by nearby circuits that are not

shielded for RFI, manifesting as a lower frequency noise signal. If possible, place the

antenna at least 1 foot away from the transceiver module, and 3 feet from other circuit boards

and obstructions. Place sensitive circuits in a grounded metal casing to keep out RFI.

Sign-on banner or modem control mode prompt is unreadable.

If the problem is repeatable, check whether the data rates between host and transceiver

match.

Range is extremely limited.

This is usually a sign of poor antenna coupling. Check that the antenna is firmly connected.

If possible, remove any obstructions in the near field of the antenna (~3' radius).

Transmitting terminal flashes CTS occasionally.

This indicates that the transmitter is unable to reliably get its data across. This may be the

result of an interfering signal, but most often is caused by overloading of the network.

Adjusting the protocol parameters may increase the network efficiency.

Receiving terminal drops characters periodically.

Set the number of retries to a high number and send a few characters. Check that the

transmitted data can get through under these conditions. Sometimes this symptom is caused

by an application that is explicitly dependent on the timing of the received data stream. The

nature of the packetized RF channel imposes a degree of unpredictability in the end-to-end

transmission delay.

7. APPENDICES

7.1. Technical Specifications

7.1.1. Power Specifications

Vcc Input Range: 3.3v to 10.0v

Vcc Ripple: <1%

Operating Temperature Range: -20C to +70C

Current Consumption (Max transmit power, 230.4Kbps I/O)

Mode Remote Base Station

Sleep 50µA N/A

Standby 20mA N/A

Typical 50mA 120mA

Peak (Tx) 200mA 200mA

7.1.2. RF Specifications

FCC Certification Part 15.247, no license required

ETSI (European) Certification brETSI 300.328, no license required

Rated RF Power +18 dBm (+20 dBm effective radiated)

Line-of-site Range approx. 6/10 of a mile

Frequency Range 2401 – 2480MHz

Number of Channels 75 (France: 33, Spain & Japan: 25)

Receiver Sensitivity -93dBm

Channel Data Rate 460Kbps

IF Adjacent Channel Rejection >55dB

7.2.2. Mechanical Specifications

Weight 35g

Dimensions (including shield) 80.2 x 46.5 x 8.6mm

(refer to section 7.6 for mechanical drawing)

RF Connector:WIT Huber/Suhner: 85 MMCX 50-0-1

Mating Huber/Suhner: 11 MMCX-50-2-3 (straight)

Huber/Suhner: 16 MMCX-50-2-2 (rt. angle)

Data/Power Connector:

WIT Samtec: DIS5-108-51-L-D

Mating Samtec: FFSD-08 (IDC cable)

Samtec: CLP-108-02-G-D (PCB mount)

7.3. Serial Connector Pinouts

Signal WIT2410M

OEM Pinout WIT2410E

DB9 Pinout

GND 1 5

TXD 2 3

RXD 3 2

CFG 4 -

RTS 5 7

SLEEP 6 4

DCD 7 1

CTS 8 8

The WIT2410E is wired as a DTE device and as such can be connected to DTE devices such

as PCs with a straight-through cable. When connecting a WIT2410E to a DCE device, a

“null modem” cable is required. To effect a null modem cable, cross-wire TXD and RXD

and connect ground. The WIT2410E can operate with just these three wires connected.

However, as the WIT2410 does not support software flow control, there will be no flow

control in this mode. If the DCE device fails to respond, connect DCD from the WIT2410E

to the DTR and RTS inputs to activate the DCE device whenever the WIT2410 asserts

carrier.

When connecting to the WIT2410M, make sure that all of the inputs (TXD, CFG, RTS and

SLEEP) are terminated for proper operation.

7.4. Approved Antennas

The WIT2410M is designed to ensure that no antenna other than the one fitted shall be used

with the device. The end user must permanently affix the antenna by using an adhesive on

the coupling such as Loctite, or ensure the antenna has a unique coupling. The table below

lists the antennas which can be purchased directly from Digital Wireless Corporation.

Contact DWC Technical Support with any questions.

Description Gain Part Number Coupling

YD24/15 Yagi Directional 14 dB YAGI2415 N

Om24/9 Omnidirectional 9 dB OMNI249 N

DWC Patch 6 dB PA2400 MMCX

Dipole 2 dB RWA249R Reverse SMA

7.5. Technical Support

For technical support call Digital Wireless Corporation at (770) 564-5540 between the hours

of 8:30AM and 5:30PM Eastern Time.

7.6. Mechanical Drawing

7.7. Warranty

Seller warrants solely to Buyer that the goods delivered hereunder shall be free from defects

in materials and workmanship, when given normal, proper and intended usage, for twelve (12)

months from the date of delivery to Buyer. Seller agrees to repair or replace at its option and

without cost to Buyer all defective goods sold hereunder, provided that Buyer has given Seller

written notice of such warranty claim within such warranty period. All goods returned to

Seller for repair or replacement must be sent freight prepaid to Seller’s plant, provided that

Buyer first obtain from Seller a Return Goods Authorization before any such return. Seller

shall have no obligation to make repairs or replacements which are required by normal wear

and tear, or which result, in whole or in part, from catastrophe, fault or negligence of Buyer,

or from improper or unauthorized use of the goods, or use of the goods in a manner for which

they are not designed, or by causes external to the goods such as, but not limited to, power

failure. No suit or action shall be brought against Seller more than twelve (12) months after

the related cause of action has occurred. Buyer has not relied and shall not rely on any oral

representation regarding the goods sold hereunder, and any oral representation shall not bind

Seller and shall not be a part of any warranty.

THE PROVISIONS OF THE FOREGOING WARRANTY ARE IN LIEU OF ANY

OTHER WARRANTY, WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL

(INCLUDING ANY WARRANTY OR MERCHANT ABILITY OR FITNESS FOR A

PARTICULAR PURPOSE). SELLER’S LIABILITY ARISING OUT OF THE

MANUFACTURE, SALE OR SUPPLYING OF THE GOODS OR THEIR USE OR

DISPOSITION, WHETHER BASED UPON WARRANTY, CONTRACT, TORT OR

OTHERWISE, SHALL NOT EXCEED THE ACTUAL PURCHASE PRICE PAID BY

BUYER FOR THE GOODS. IN NO EVENT SHALL SELLER BE LIABLE TO

BUYER OR ANY OTHER PERSON OR ENTITY FOR SPECIAL, INCIDENTAL OR

CONSEQUENTIAL DAMAGES, INCLUDING, BUT NOT LIMITED TO, LOSS OF

PROFITS, LOSS OF DATA OR LOSS OF USE DAMAGES ARISING OUT OF THE

MANUFACTURE, SALE OR SUPPLYING OF THE GOODS. THE FOREGOING

WARRANTY EXTENDS TO BUYER ONLY AND SHALL NOT BE APPLICABLE

TO ANY OTHER PERSON OR ENTITY INCLUDING, WITHOUT LIMITATION,

CUSTOMERS OF BUYERS.

Murata Electronics North America 2410M Modular 2.4 GHz Transceiver User Manual Integration Guide

Murata Electronics North America Modular 2.4 GHz Transceiver Integration Guide

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