Linx Technologies CMD-HHTX-XXXA Full Size Handheld Transmitter User Manual
Linx Technologies Full Size Handheld Transmitter Users Manual
Users Manual

DESCRIPTION
The Linx CMD-HHTX-*** Full-Size Handheld
transmitter is ideal for general-purpose remote
control and command applications. As a part of
our Holtek encoder-based OEM family, it has
been pre-certified for FCC Part 15, Industry
Canada, and European CE (433MHz only)
compliance, reducing costs and time to market.
Available in 315, 418 (standard), or 433.92MHz,
this handheld remote has a transmission range
of up to 750 feet when combined with the LR
Series receiver. The transmitter unit can be
configured with 1 to 8 buttons and the keypad
and labeling can be modified to meet specific
OEM customer requirements. Selectable
addressing provides security and allows the
creation of up to 256 distinct transmitter-
receiver relationships. The address can be
easily changed via an externally accessible DIP
switch. The transmission can be decoded using
a matching Linx Function Module, KH2 Series
receiver / decoder, or a Linx LR or LT Series
receiver paired with a decoder IC or
microcontroller. The unit uses a single 3V
CR2032 lithium button cell.
FEATURES
nFCC, Canada, and CE pre-certified
n1 to 8 buttons
nSmall package
nCustomizable keypad
APPLICATIONS INCLUDE
nGeneral Remote Control
nKeyless Entry
nGarage / Gate Openers
nLighting Control
nCall Systems
nHome / Industrial Automation
OEM HANDHELD TRANSMITTER DATA GUIDE
0.17"
0.62"
3.35"
1.81"
Revised 7/27/10
Figure 1: Package Dimensions
WIRELESS MADE SIMPLE
®
OEM Configurations
With a one-time NRE and minimum
order, Linx can configure the keypad
and label areas to meet your specific
requirements. Contact Linx for details.
2
1
3
4
A
B
C
D
ON
ON
ON
ON
FASCO
Lights
Spa
O
N
O
N
O
N
O
FF
O
FF
O
FF
Pool
PART # DESCRIPTION
CMD-HHTX-*** OEM Handheld Transmitter
EVAL-***-HHTX HHTX Evaluation Kit
*** = 315, 418 (Standard), 433.92 MHz
ORDERING INFORMATION

Page 2 Page 3
1. Characterized, but not tested
Notes
ELECTRICAL SPECIFICATIONS
Parameter Designation Min. Typical Max. Units Notes
POWER SUPPLY
Operating Voltage VCC 2.1 3.0 3.6 VDC –
Supply Current ICC –3.4–mA–
Power-Down Current IPDN –5.0–nA1
TRANSMITTER SECTION
Transmit Frequency Range: FC
CMD-HHTX-315 – 315 – MHz –
CMD-HHTX-418 – 418 – MHz –
CMD-HHTX-433 – 433.92 – MHz –
Center Frequency Accuracy – -50 – +50 kHz –
ENVIRONMENTAL
Operating Temperature Range – -30 – +70 °C 1
SETTING THE TRANSMITTER ADDRESS
The Full-Size Handheld transmitter allows
the selection of one of 256 unique
addresses. All transmitters are supplied set
to the same address. To avoid contention
with other units or to create unique
relationships, the address can be changed.
This is accomplished using internal DIP
switches as shown. The switches are
accessed by removing the rear cover as for
battery replacement.
If the switch is on, the address line is
connected to ground, otherwise it is
floating. The receiver’s address must match
exactly in order for the units to communicate. Application Note AN-00300
describes in detail how to set the address to match any of the receivers offered
by Linx. This note can be found in the Support section of the Linx web site,
www.linxtechnologies.com.
CMD-HHTX BUTTON ASSIGNMENTS
This diagram illustrates the relationship between the button locations and
encoder data lines.
D7 D6
D5 D4
D3 D2
D1 D0
Figure 3: CMD-HHTX-*** Button Assignments
ON OFF
A7 = 1
A6 = 2
A5 = 3
A4 = 4
A3 = 5
A2 = 6
A1 = 7
A0 = 8
Figure 2: DIP Switch Assignments
THEORY OF OPERATION
The CMD-HHTX-*** Full-Size Handheld transmitter combines the LR Series
transmitter and an antenna with an on-board Holtek HT640 encoder IC to form a
simple, yet highly reliable, RF remote-control transmitter. The LR Series
transmitter is a low-cost, high-performance synthesized ASK / OOK transmitter.
The transmitter’s synthesized architecture delivers outstanding stability and
frequency accuracy, while minimizing the effects of antenna port loading and
mismatching. This reduces or eliminates frequency pulling, bit contraction, and
other negative effects that are common to SAW-based transmitter architectures,
providing a significantly higher level of performance and reliability.
When a button is pressed on the transmitter, power is applied to the internal
circuitry and the encoder IC is enabled. The encoder detects the logic states of
the address lines and button data lines. These states are formatted into a three-
word transmission cycle that continues until the button is released. The encoder
data is used to modulate the transmitter, which, through the antenna, conveys
the data into free space. On the receiver side, a decoder IC or custom
microcontroller is used to check the transmitter’s address bits against the
address settings of the receiving device. If a match is confirmed, the decoder’s
outputs are set to replicate the transmitter’s button states. These outputs can
then be used to activate external circuitry required by the application.
The transmitter is compatible with several Linx receiver products, including the
LR, KH2, LT, and OEM product families. When the transmitter is combined with
an LR Series receiver and the HT658 decoder chip, ranges of up to 750 feet are
possible. Applications operating over shorter distances will also benefit from the
increased link reliability and superior noise immunity provided by the LR Series
receiver.

Page 4 Page 5
Place the above statement in the instruction manual or insert card.
COMPLIANCE REQUIREMENTS
The CMD-HHTX-*** has been pre-certified by Linx for FCC Part 15 and Industry
Canada RSP-100 compliance. The 433.92MHz version has also been tested for
CE compliance for use in the European Union. The 315MHz and 418MHz
versions are not legal for use in Europe.
LABELING / INSTRUCTION REQUIREMENTS
The CMD-HHTX-*** Full-Size Handheld transmitter has already been labeled in
accordance with FCC, Industry Canada, and CE regulations in effect as of the
date of this document. No further labeling of the unit is needed; however, it is
necessary to include the following statement in the end product’s instruction
manual or insert card for FCC compliance. Industry Canada only requires the
shaded portion. EU does not require a statement.
Figure 5: CMD-HHTX-*** Assembly
CONTENTION CONSIDERATIONS
It is important to understand that only one transmitter at a time can be activated
within a reception area. While the transmitted signal consists of encoded digital
data, only one carrier of any particular frequency can occupy airspace without
contention at any given time. If two transmitters are activated in the same area
at the same time, then the signals will interfere with each other and the decoder
will not see a valid transmission, so it will not take any action.
BATTERY REPLACEMENT
The remote unit utilizes a standard CR2032 lithium
button cell. In normal use, it will provide 1 to 2 years
of operation. To replace the battery, remove the
screw in the middle of the back cover. Once the unit
is open, remove the battery by depressing the
release finger on the battery holder as shown.
Replace it with the same type of battery while
observing the polarity shown in the adjacent figure.
There may be the risk of explosion if the battery is
replaced by the wrong type. Replace it with the same
type of battery while observing the polarity shown in
the adjacent figure.
ASSEMBLY DIAGRAM
Battery Release
+
Figure 4: Battery Access
INSTRUCTION TO THE USER
This device complies with Part 15 of the FCC Rules.
Operation of this device is subject to the following two conditions:
(1) This device may not cause harmful interference, and
(2) this device must accept any interference received, including interference
that may cause undesired operation.
This equipment has been tested and found to comply with the limits for a Class
B digital device, pursuant to Part 15 of the FCC Rules. These limits are
designed to provide reasonable protection against harmful interference in a
residential installation. This equipment generates, uses and can radiate radio
frequency energy and, if not installed and used in accordance with the
instructions, may cause harmful interference to radio communications.
However, there is no guarantee that interference will not occur in a particular
installation. If this equipment does cause harmful interference to radio or
television reception, which can be determined by turning the equipment off and
on, the user is encouraged to try to correct the interference by one or more of
the following measures:
Reorient or relocate the receiving antenna.
Increase the separation between the equipment and receiver.
Connect the equipment into an outlet on a circuit different from that to which the
receiver is connected.
Consult the dealer or an experienced radio/TV technician for help.
This equipment has been certified to comply with the limits for a Class B
computing device, pursuant to FCC Rules. In order to maintain compliance with
FCC regulations, shielded cables must be used with this equipment. Operation
with non-approved equipment or unshielded cables is likely to result in
interference to radio and TV reception. The user is cautioned that changes and
modifications made to the equipment without the approval of manufacturer
could void the user’s authority to operate this equipment.

Page 7Page 6
Figure 7: CMD-HHTX-*** Schematic
RECEIVERS
There are four options for receivers within the Linx
product line. The first option is to use one of the OEM
Function Modules, such as the Relay Module or the AC
Wall Module. These items are also pre-certified and
can be immediately included in a product.
The other options are to use one of the Linx receiver
modules. The signal sent by the OEM Handheld
transmitter can be received by the LR Series receiver
module or the LT Series transceiver module. These
modules can be connected to the Holtek HT658
decoder to decode the signal, or a custom
microcontroller can be programmed to decode it and
take specific action.
The KH2 Series offers a slightly simpler solution by
combining the LR Series receiver and the HT658
decoder in a single package.
When a button is pressed on the transmitter, a
corresponding line on the decoder will go high (as long
as the addresses match). This can then be connected
to whatever circuitry is required by the application.
Application Note AN-00300 discusses in detail how to
set the addresses on all of the units. Data guides for all
of the receivers, the HT640 encoder, and the HT658
decoder can be found on the Linx Technologies
website, www.linxtechnologies.com.
TYPICAL APPLICATIONS
The outstanding sensitivity of the
LR Series receiver offers the best
range when used with the
Handheld transmitter. When using
the LR Series receiver, the Holtek
HT658 decoder chip should be
used to decode the received signal.
This decoder has ten address lines
that must match the transmitter
address lines. A DIP switch is
commonly used to set these, but
they can also be hardwired. If the
address lines match, when a button
on the transmitter is pressed a
corresponding data line on the
decoder (D0-D7) will go high.
These data lines can then be
connected to external circuitry to
perform whatever function is
required by the application.
G
N
D
R1
390k
G
N
D
G
N
D
V
CC
V
CC
D1
1
D2
2
D
3
3
D4
4
D
5
5
D
6
6
D7
7
VT
8
DIN
9
OSC1
1
0
OSC2
11
G
N
D
12
A
0
1
3
A
1
14
A
2
1
5
A
3
1
6
A4
17
A
5
1
8
A
6
1
9
A7
2
0
A
8
21
A
9
22
D
0
2
3
V
CC
24
HT
658
N
C
1
N
C
2
N
C
3
G
N
D
4
V
CC
5
PDN
6
R
SSI
7
DATA
8
N
C
9
N
C
1
0
N
C
11
N
C
12
N
C
1
3
N
C
14
G
N
D
1
5
ANT
1
6
RXM
-
LR
G
N
D
Figure 6: LR Receiver and HT658 Schematic
MEMBRANE SWITCH
VCC
VCC
R1
390K
RF
1
GND
2
GND
3
GND
4
GND
5
GND
6
ANT1
ANT-XXX-SP
R2
100K
D1
1
D2
2
D3
3
D4
4
D5
5
D6
6
D7
7
DOUT
8
TE
9
OSC1
10
OSC2
11
GND
12 A0 13
A1 14
A2 15
A3 16
A4 17
A5 18
A6 19
A7 20
A8 21
A9 22
D0 23
VCC 24
U1
HT-640
VCC
GND
GND
GND
GND
GND
VCC
GND
R3
GND
GND
VCC
SW1 1
SW2 2
SW3 3
SW4 4
SW5 5
SW6 6
SW7 7
SW8 8
COM 9
SM1
1
2
3
4
U2
DPAK-X2
1
2
3
4
U3
DPAK-X2
1
2
3
4
U4
DPAK-X2
1
2
3
4
U5
DPAK-X2
GND
1
DATA IN
2
GND
3
IADJ/VCC
4RF OUT 5
GND 6
VCC 7
PDN 8
TX1
TXM-XXX-LR
1
2
3
4
5
6
7
8
16
15
14
13
12
11
10
9
S1
SW-DIP-8
B1
BATT
Set for
FCC compliance

LINX TECHNOLOGIES, INC.
159 ORT LANE
MERLIN, OR 97532
PHONE: (541) 471-6256
FAX: (541) 471-6251
www.linxtechnologies.com
U.S. CORPORATE HEADQUARTERS
WIRELESS MADE SIMPLE
®
Linx Technologies is continually striving to improve the quality and function of its products. For this reason,
we reserve the right to make changes to our products without notice. The information contained in this Data
Guide is believed to be accurate as of the time of publication. Specifications are based on representative lot
samples. Values may vary from lot-to-lot and are not guaranteed. "Typical" parameters can and do vary over
lots and application. Linx Technologies makes no guarantee, warranty, or representation regarding the
suitability of any product for use in any specific application. It is the customer's responsibility to verify the
suitability of the part for the intended application. NO LINX PRODUCT IS INTENDED FOR USE IN ANY
APPLICATION WHERE THE SAFETY OF LIFE OR PROPERTY IS AT RISK.
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PARTICULAR PURPOSE. IN NO EVENT SHALL LINX TECHNOLOGIES BE LIABLE FOR ANY OF
CUSTOMER'S INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY FROM ANY DEFECTIVE
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sold by Linx Technologies to Customer. Under no conditions will Linx Technologies be responsible for
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refund limited to the original product purchase price. Devices described in this publication may contain
proprietary, patented, or copyrighted techniques, components, or materials. Under no circumstances shall
any user be conveyed any license or right to the use or ownership of such items.
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© 2010 by Linx Technologies, Inc. The stylized Linx logo,
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Printed in U.S.A.