Data Critical 01DR-10000 Wireless Access Point (AP) for medical monitoring User Manual users manual

Data Critical Corporation Wireless Access Point (AP) for medical monitoring users manual

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users manual

SNAP2410/2414/2420Spread SpectrumNetwork Access PointsInstallation GuideApril 20, 2000One Meca WayNorcross, Georgia 30093www.digital-wireless.com(770) 564-5540
Transmitter Module FCCID: HSW-2410M.Note: This unit has been tested and found to complywith the limits for a class A digital device, pursuant topart 15 of the FCC Rules. These limits are designed toprovide reasonable protection against harmfulinterference when the equipment is operated in acommercial environment. This equipment generates,uses, and can radiate radio frequency energy and, if notinstalled and used in accordance with the instructionmanual, may cause harmful interference to radiocommunications. Operation of this equipment in aresidential area is likely to cause harmful interferencein which case the user will be required to correct theinterference at his own expense. Commensurate withEIRP limits specified in FCC Rules 15.247b, thisdevice may not be used with antennas that exceed36dB of gain in point-to-point applications or 16dB ofgain in multi-point applications.
Table of ContentsIntroduction ...................................................................................................... 1Getting Started................................................................................................. 2Connecting the SNAP.................................................................................... 2SNAP Status Indicators ................................................................................. 3Configuring the SNAP.................................................................................... 3SNAP Operation............................................................................................... 5Overview....................................................................................................... 5TCP/IP Addresses ......................................................................................... 5Seamless Roaming........................................................................................ 6Synchronization............................................................................................. 7AP Mode Operation ....................................................................................... 7PPP Operation .............................................................................................. 84-Port Hub..................................................................................................... 8SNAP Command Set........................................................................................ 9SNAP System Commands............................................................................. 9Ethernet Commands.....................................................................................10SNAP Radio Commands...............................................................................11AP Mode Commands....................................................................................12PPP Mode Commands .................................................................................13Radio Modem Configuration ............................................................................15Radio Commands.........................................................................................15SNAP Datagram Protocol (SDP)......................................................................17Overview......................................................................................................17SDP Header.................................................................................................17SDP Messages.............................................................................................18Troubleshooting ..............................................................................................21Technical Support.........................................................................................21Quick Reference..............................................................................................22Specifications..................................................................................................25Warranty .........................................................................................................26
2000 Digital Wireless Corporation 1042000INTRODUCTIONThe SNAP2410 family of products from Digital Wireless Corporation provides Ethernetconnectivity to networks of WIT2410 radios. Built around the WIT2410, SNAP productsprovide a 10BaseT connection to Ethernet networks and function as base stations forremote devices containing WIT2410 transceivers. By supporting seamless roaming,multiple SNAPs can be connected to a network to provide practically unlimited coveragearea. To simplify system installation some SNAPs have built-in 4-port hubs with anuplink port. In addition, these SNAPs allow for power to be distributed through the hubports.Depending on the model, SNAPs have one or two WIT2410 transceivers. Each radio cansupport 62 simultaneous remotes. Thus SNAPs can support up to 124 simultaneousremotes. Each remote radio has a unique ID number, so the number of remotes that cancommunicate with a SNAP is unlimited, subject to a limit of 62 remotes at any one time.The communication between the SNAP and the WIT2410 remotes is performed using theWIT2410 over-the-air protocol. Thus the SNAP products are 802.3 compatible but not802.11 compatible. By using the 460Kbps over-the-air data rate the WIT2410 protocol,the full range of WIT2410 radios is realized, three times the range of most 802.11products.The SNAPs enjoy the same benefits of frequency-hopping spread spectrum technologythat the WIT2410s do. Namely, the immunity to multipath fading and resistance tojamming that is provided by changing frequency every few milliseconds. Operating in the2.4GHz ISM band, SNAPs can be used license-free worldwide and are not subject to thecongestion in the 900MHz band caused by cordless telephones.The SNAP has two modes of operation, AP and PPP. The default mode is the AP mode.In this mode the SNAP uses a special protocol mode called SDP(SNAP DatagramProtocol). In order to send receive or transmit data from the SNAP, the applicationsoftware must use this protocol. The user may use the API roam library included withthe SNAP to help shorten software development.The SNAP can also be configured as a PPP server. This allows any computer with aremote to connect to the same network as the SNAP. These computers then could accessany files on the network and support browser-based applications.
2000 Digital Wireless Corporation 2042000GETTING STARTEDThe SNAP family of wireless Ethernet modems are easy to install and operate. In mostinstances, the only installation steps will be setting IP addresses, selecting one modem asthe master and connecting the antenna, power and Ethernet cable.Connecting the SNAPFigure 1 identifies the various connectors on the rear of the SNAP2410.Figure 1. SNAP Rear Panel DiagramThe antenna connector is a TNC type connector. An antenna may be connected directlyto this connector. Alternatively, an antenna may be located away from the SNAP usingRF cable to connect the SNAP to the antenna. Digital Wireless does not recommendusing RF cables longer than 5 feet. If more distance is required between the SNAP andthe antenna, high-quality, low-loss RF feed line must be used.The 10BaseT Ethernet connector is the standard RJ-45 connector. The connector is wiredto be able to connect directly to an Ethernet hub using a straight-through cable. If it isdesired to connect the SNAP directly to a PC without a hub, the SNAP must beconnected with a cross-over cable.The synchronizing signals are provided for special applications where multiple masterSNAPs are employed in an environment with slave SNAPs that are moving. Thesynchronizing signals are RS-485 levels and may be connected using an RJ-11 connector.In most instances the synchronizing signals are not required and may be left unconnected.The power connector is a 2-pin DIN type connector. The provided AC adapter provides a9 volt power level to the SNAP. The SNAP can accept DC voltages ranging between7VDC and 26VDC if alternative power supplies are to be used.Power Connector Synchronizing Signals 10BaseT Ethernet ConnectorTNC Antenna Connector
2000 Digital Wireless Corporation 3042000Figure 2. SNAP2410 Front Panel DiagramThe Configuration Port is an RS-232 serial port that may be used to configure the SNAP.This is useful when the default IP address of the SNAP cannot be used with the existingnetwork preventing configuration through a telnet session. See the section Configuringthe SNAP for details of using this port.SNAP Status IndicatorsThe PWR indicator on the front panel indicates that power is applied to the SNAP andthat the power switch is in the ON position.TXD and RXD are indicators of data activity. They indicate the transmission andreception of data over the Ethernet connection. Note that these LEDs can be active evenwhen the SNAP has no remote radios registered.The COLL indicator is illuminated whenever packets collide on the network segment towhich the SEM is connected. As such, this is rough indicator of the level of traffic on thenetwork segment. If this LED is glowing brightly on a continuous basis, the throughputof the SEM may appear to be reduced.The LINK indicator when illuminated indicates a good connection to the Ethernetnetwork. If this LED is not on, it can indicate a cross-wired connection between theSNAP and the network. It may also indicate a faulty cable connection.Configuring the SNAPSNAPs are shipped from the factory with default settings that include a default IP addressof 192.168.0.254. The network that the SNAP is connecting to must be compatible with10BaseT products. The SNAP will not work if the network only supports 100BaseTproducts. Before connecting a default configured SNAP to an active network, ask thenetwork system administrator to make sure that the default IP number will not cause anySNAP 24102.4 GHz SPREAD SPECTRUM WIRELESS ETHERNET MODEMPower Switch Status Indicators Configuration Port
2000 Digital Wireless Corporation 4042000problems on the network and that the SNAP will be recognized by the network. If thedefault IP address conflicts with a device on the existing network, the SNAP will need tobe configured through the serial port.The SNAP can be configured two ways. The first is through the serial port. The settingsfor the serial port are 38400 baud, 8 data bits, 1 stop bit, and no parity. WinSNAP willautomatically find the appropriate serial port and configure the serial port settings foryou. The software will inform you of its progress and any problems that arise. After afew seconds the SNAP firmware version is displayed followed by the SNAP> prompt.The second configuration method is through a telnet session. Most telnet programs workwith the SNAP. Windows 95/98/NT/2000 have a telnet program that works with theSNAP. If there are no conflicts with the default IP number, initiate a telnet session to theSNAP. A telnet session can be started by clicking on Start->Run if you have Windows95/98/NT/2000 and the TCP/IP client has been installed. Enter the following informationin the dialog box:telnet 192.168.0.254A telnet window will open up. The first line is the version of the SNAP firmwarefollowed by the prompt:SNAP>To change the IP number of the SNAP, use the ip command.ip <xxx.xxx.xxx.xxx> {yyy.yyy.yyy.yyy}Where x is the new IP address, and y is the optional netmask number.Store the changed configuration parameters in non-volatile memory with the savecommand:save<CR>The SNAP will report back the time it took to the save the information. Reset the SNAPby typing:reset<CR>The SNAP can also be reset by cycling power. Whenever a reset is executed on theSNAP, the telnet session will be lost. It will take the SNAP about 30 seconds toreinitialize after a reset or after cycling power.Note: The save and reset commands must be entered after modifying thedefault configuration. Failure to do so will result in the factory defaults tobe used.
2000 Digital Wireless Corporation 5042000SNAP OPERATIONOverviewAt the most basic level, SNAPs can be thought of as Ethernet-to-serial interface adapters.That is, they take data from a host application over a 10BaseT Ethernet connection,remove the Ethernet header information, format the data for WIT2410 radios andtransmit the data to the on-board WIT2410 through a high-speed serial interface. In theother data flow direction, the on-board WIT2410 receives data from a remote WIT2410device. The SNAP takes this data and provides the necessary Ethernet datagramencapsulation and transmits the datagram to the host application over the connectednetwork.A SNAP can be used standalone, or a group of SNAPs can be connected together througha 10BaseT hub to provide seamless roaming over a larger area. When seamless roamingoperation is desired, the SNAPs must be synchronized with each other. Thissynchronization is accomplished either over the Ethernet network or through adifferential Sync signal when time delay devices (such as routers) are between SNAPs.See the section on Synchronization for details.Communication between the host application SNAPs can occur at one of two levels.Provided with the SNAP is a library of C routines that constitute a high level API forworkstation-based applications. Alternatively, host applications can communicate with aSNAP using the SNAP Datagram Protocol (SDP). This protocol is described in detaillater in this manual.The SNAP has a serial Configuration port in addition to the 10BaseT port. This portallows configuration of the SNAP without having to connect it to a network. TheWinSNAP configuration utility provided with the SNAP is used to configure the SNAPthrough the serial Configuration port. Any configuration of the SNAP can be performedusing either the Configuration port or over the network.TCP/IP AddressesEach SNAP must be configured with a unique IP address that is appropriate for thenetwork where the SNAP will be used. The IP address can be set using the ip commandthrough the serial-port interface. The ip command takes one or two parameters. The firstparameter specifies the IP address for the SNAP, and the second optional parameter, ifpresent, specifies the netmask for the SNAP. If the second parameter is not used, thenetmask is set to the default netmask for the IP address specified. For example, thecommand: ip 192.168.0.1will set the SNAP’s IP address to 192.168.0.1 and the netmask will remain255.255.255.0.
2000 Digital Wireless Corporation 6042000The command:ip 192.168.1.233 255.255.255.192will set the SNAP’s IP address to 192.168.1.233 and will change the netmask to255.255.255.192. The ip command without any parameters will display the currentsetting of the IP address and netmask. The SNAP includes a simple ping command thatcan be used to test the IP address and routing table settings.The SNAP can also obtain its IP address from a BOOTP server if one is present in thenetwork. The BOOTP server will require the Ethernet hardware MAC address to be ableto assign the IP address to the SNAP. The Ethernet hardwate MAC address of the SNAPis configured as 00:30:66:XX:YY:ZZ, where XX:YY:ZZ is the unique ID of the SNAP’s“radio A”.The route command can be used to modify and display the IP routing table entries. Todisplay the routing table, use the route list command. There will always be one entry inthe routing table that corresponds to the IP address of the SNAP. For most applications,if any routing table entries are required, it will be sufficient to set a default route. To setthe default route, use the command:route add default <gwaddr>where <gwaddr> is the IP address of the default gateway (usually a router or routinghost). To remove the default route, use the command “route del default”. To add a routeto a particular network or host, use the command “route add <dest> <gw> [<netmask>]”,where “<dest>” is the destination network or host IP address, “<gw>” is the IP address ofthe gateway, and the optional “<netmask>” is the netmask which defines the destinationnetwork.Seamless RoamingThe SNAP2410 allows remote radios to seamlessly roam between multiple SNAP2410.The remote radios can also be configured not to roam if this is the required operatingcondition. In order for the remote to be able to roam seamless the <wg> parameter mustbe set to 2. When the RSSI (receive signal strength indictor) of the remote reaches acertain threshold, the remote will start looking for another SNAP with a higher RSSI.The SNAP will be notified with a CONNECT and DISCONNECT packet when a remoteleaves or connects with a SNAP.To facilitate seamless roaming among a group of SNAPs, the SNAPs use Ethernetpackets to synchronize time relative to each other. A single “master” SNAP willbroadcast (or multicast) special UDP datagrams to the “slave” SNAPs to deliver timinginformation through the network. The SNAPs can also synchronize with one another byRJ-11 cable (telephone cable). The RJ-11 method of synchronization uses a daisy chainfashion to connect the SNAPs together. The SNAPs need to be synchronized this way if
2000 Digital Wireless Corporation 7042000the ethernet packets can not be transmitted in a timely manner, such as going through arouter.SynchronizationThe SNAP uses broadcast or multicast datagrams for time synchronization. The defaultis for the master SNAP to broadcast datagrams to the 255.255.255.255 all-hosts IPbroadcast address. Using the “sys xcast <ipaddr>”, SNAPs can be configured to use amore limited IP broadcast address, or a multicast address. All SNAPs in a networkshould be configured with the same “xcast” address. The use of multicast addresses ispreferred so that synchronization datagrams do not interfere with hosts other than theSNAPs. Note that the SNAPs use UDP port 2410 as the source and destination UDP portnumbers in the synchronization packets.The command “sync master” is used to set a SNAP to the master for timesynchronization, and the command “sync slave” is used to set a SNAP to be a slave fortime synchronization. There should be one master in a given network, even if there isonly one SNAP in the network.There may be a time when there will be SNAP on different sides of a network router.This situation could cause the SNAPs not to be synchronized. This is where the RJ-11sync connectors can be used. If the remotes will need to be able to roam between theSNAP located on different sides of the network router, the SNAP will have to beconnected together using the RJ-11 connectors. The cable will only need to be twotwisted pair. This is the same as regular phone cable. If there are more than two SNAPsin the network, the SNAPs will need to be daisy chained together.AP Mode OperationThe default operating mode of the SNAP is AP mode. This mode is optimized forcommunications between a workstation or workstations on an Ethernet network and anetwork of WIT2410-based devices. The AP mode assumes that there is limitedintelligence in the remote host. The AP mode is designed to allow the remote hostdevices to send and receive data to the remote WIT2410 in transparent mode.Data exchanges between the SNAP and workstations on the network are made using theSDP protocol. This protocol is described in detail later on in this manual. To shortensoftware development time, a C library is included that will help with the SNAP protocol.roamlib will help in the developing the software needed to talk to the remote radios fromthe SNAP. Also included is a simple multi-window (one per remote) ethernet chatprogram, roam.exe. This program allows the user to send data to the SNAP and to theremote. This program is based on the roamlib. In order for roam.exe to work the “sysxcast” must be 224.5.5.5, the “sdp” must be 224.1.2.3 and the source and destination portnumbers must be 2411 and 2412 respectively. These are the default settings. Using theroam library requires the use of winsock.dll. This file should already be included on anyWindows 95/98/NT PC that has TCP/IP installed as a protocol.
2000 Digital Wireless Corporation 8042000PPP OperationThe SNAP can be configured to operate as a PPP (Point-Point Protocol) server. PPP is adial-in network connection that allows TCP/IP communication. A PPP connection allowsa remote connected to a computer to be connected to network that the SNAP is on usingthe TCP/IP protocol. In order to operate the SNAP as a PPP server, the followingsequence of commands must be entered.sys mode PPPsaveresetThe SNAP will also allow the user to specify the starting IP address for the remotes thatlogon. The first remote to logon will receive the IP address specified below. The SNAPwill then add one to the IP address for the next remote to login.ppp base <IP address>Included in the appendix is a listing of a Windows modem definition file. This inf filewill work on Windows 95/98/2000/NT for a remote WIT2410 modem device connectedto a serial port. The WIT2410-based modem device needs to be added as a new modemusing the standard Windows procedures. When installed, Windows dial-up networkingcan be used to create a PPP session between the remote PC and the SNAP. The PPPmode of the SNAP also works with various versions of UNIX and LINUX. ContactDigital Wireless Technical Support for details.4-Port HubThe SNAP2414 model includes a built-in 4-port hub. Even though there are 5 ethernetports, only four of them can be used. There is an uplink port that can be used to connectto another SNAP or hub. This uplink port is connected to the 4th ethernet port. The hubwill not work correctly if a connection is made to both of these ports. This hub will onlysupport 10BaseT networks.
2000 Digital Wireless Corporation 9042000SNAP COMMAND SETThe SNAP supports a series of commands that allow for configuring the Ethernetinterface as well as the radio parameters of the on-board WIT2410. These commands canbe entered during a telnet session or by using the WinSNAP24 utility when the SNAP>prompt is displayed. The commands are summarized here with detailed explanationsfollowing.SNAP System CommandsCommand Descriptionecho Toggles user screen echo modehelp Displays command help screenreset Resets the SNAP activating changed configurationparameterssave Stores current configuration to memorysys [helpmode [AP|PPP]outmax <1-212>xcast [<b/mcastaddr>]Displays help screen for commandSets SNAP to Access Point or PPP server modeSet maximum transmit packet lengthShows broadcast/multicast addressSets broadcast/multicast addressversion Diplays SNAP firmware versionecho Toggles the user screen mode to echo characters typed by the user. Default ison. If echo is turned off, characters typed will not be displayed on the screenunless echoed by the terminal program.help Displays a list of all the SNAP commands. Most commands that require aparameter also have a help mode that displays the help screen for thatcommand.reset Resets the SNAP and loads saved parameters into active memory. Alsocauses the SNAP to reinitialize which can take 30 seconds. If reset is issuedbefore the save command, the new parameters are lost and the last savedparameters are used.save Saves changed parameters in non-volatile memory to be loaded on power up.Must be issued before the reset command or cycling power to have changedparameters take effect. (An exception is the sys outmax command whichbecomes active immediately after it is entered.)sys These commands modify system operation parameters. The modesubcommand is used to select the AP or PPP mode of operation. outmax setsthe length in bytes of the packets the processor in the SNAP will send to theinternal radio. This value cannot be longer than the pktlen value set in theradio. Refer to the section on radio commands for details of the Set Base Slot
2000 Digital Wireless Corporation 10 042000Size command. The xcast subcommand is used to set the multicast address tobe used when the SNAP puts data out on the network.version Displays the SNAP firmware version.Ethernet CommandsCommand Descriptionarp –a -d <ipaddr> -s <ipaddr> <eaddr>Displays arp tableDeletes arp entryAdds arp entryip [<ipaddr> <netmask>]Displays current SNAP IP addressSets SNAP IP address and optionally the netmaskpassword Sets password for telnet sessionsping <ipaddr> Pings TCP/IP hostroute [ helpadd <ipaddr|default> <gwaddr><netmask>del <ipaddr>listDisplays help screen for commandAdds IP address and netmask to route listDeletes IP address from route listLists route IP addressessocks Displays network socket informationarp Manipulates the address resolution procedure table. This command isprovided primarily as a debugging tool for setting up networks. ipaddr is thedevice IP address and eaddr is the physical Ethernet address of the deviceip Sets the IP address of the SNAP. The default IP address is 192.168.0.254.When specified netmask sets the netmask number. The default netmask is255.255.255.0.password Allows a password to be set to restrict the ability to initiate telnet sessionswith the SNAP. When this command is entered, the user is prompted for anew password which is then prompted for a second time for verification. Ifthis password is forgotten, a new password must be entered through theconfiguration port.ping sends inquiry packets to TCP/IP host specified in <ipaddr> and displays theamount of time that elapsed before a response was received. Continuouslysends requests until a key is pressed.route Displays and manipulates gateway IP addresses to route IP traffic off thesubnet. Default sets the default gateway IP address. When an IP address isentered instead of default, the gateway IP address specified will be used onlyfor traffic destined for that IP address. The route table always has an entryassociated with the IP address assigned to the SNAP.socks Displays the network socket information.
2000 Digital Wireless Corporation 11 042000SNAP Radio CommandsCommand Descriptionhop [helplength <hoplen>sequence [75|25]Displays help screen for commandInforms SNAP of radio hop dwell timeInforms SNAP of number of frequencies in radio hoppatternradio [A|B] [ helpbannernetworkcfg]Displays help screen for commandDisplays the banner of the specified radioDisplays the network number (wn) of specified radioEnters radio command moderemote [ helplistsend <handle> <data>]Displays help screen for commandDisplays remotes currently registered with the SNAPSends data to the remote specified by the handlesync [helpethermasteroverridesettingsslavewire]Displays help screen for commandSets synchronization mode to use Ethernet packetsSets SNAP as synch masterToggles master backup overrideDisplays synchronization settingsSets SNAP as synch slaveSets synchronization mode to use RS-485 wire portshop Used to inform the SNAP of the hop dwell time or the number of frequenciesin the hop pattern of the radio in the SNAP. The parameter entered forlength is in 625µs increments. The hop time specified by length shouldagree with the time specified by the ph parameter in the radio. ph is thehexadecimal value of the number of 69.4 µsec ticks in the dwell time. Thusfor each increment in length, the ph parameter should be increased by 9. Avalue of 16D corresponds to a hop dwell time of 10 msec and is the default.The sequence is the number of hop frequencies in the hop pattern in theradio in the SNAP. The default is 75 for US/ETSI operation. All otherfrequency bands, as set in the radio by the pe command, have 25 frequenciesin their hop patterns. This value is entered as a decimal number. Neither thelength nor the sequence need to be modified unless they are modified in theradio in the SNAP.radio Displays information about the configuration of the radio in the SNAP orputs the radio in configuration mode. A or B must be specified to identify towhich of the two possible radios in the SNAP the command is directed. Thebanner command returns the firmware version number and the serial numberof the radio in the SNAP. When cfg is entered, the specified radio is put intoconfiguration mode. The SNAP> is replaced with just a > prompt. At thispoint radio configuration commands may be entered. Refer to the section onradio commands in this manual for the radio commands pertaining to theSNAP. Refer to the WIT2410 Integration Guide for a complete listing ofradio commands.
2000 Digital Wireless Corporation 12 042000remote This command lists the currently registered remotes by the serial number ofthe remote radio and the assigned handle. The send subcommand will sendthe specified data to the remote with handle specified in the command. Thisis intended as a debugging mode and not an operational mode.sync These commands set the operation of the synchronization signal used inmulti-SNAP networks implementing seamless roaming. ether and wire aremutually exclusive commands and set the synchronization to occur over theEthernet or over the RS-485 signal lines. One SNAP must be configured asthe sync master and all others must be configured as sync slaves. overridetoggles the master backup override on and off.AP Mode CommandsThese commands are unique to the AP mode of operation. Each command is preceded bysdp.Command Descriptionhelp Displays help screen for commandadd <sdp> <ipaddr> <dstprt> <srcprt>Add an SDP entrycache <size> Set number of cached SDP output packetsdelete <sdp> Delete an SDP entrylist List SDP entriessdpmax <size> Set SDP maximum packet sizehelp Lists the various commands available under the sdp top level command.add Defines the IP address and port numbers that the SNAP will use when sendingand receiving SDP messages. A maximum of 4 SDP entries may be set up.They can be either unicast or multicast addresses.cache Allows the number of datagrams cached by the SNAP to be modified. Cacheddatatgrams may be requested to be retransmitted by workstations.delete Removes an SDP entry.list List SDP entries and their associated IP addresses and port numbers.max Sets the maximum number of bytes of data that will be included in a SDPdatagram before the datagram is sent. If 20ms elapses since the last bytereceived, the datagram will be sent regardless of the number of bytes in thedatagram.
2000 Digital Wireless Corporation 13 042000PPP Mode CommandsThese commands are unique to the PPP mode. They are preceded by ppp.Command Descriptionhelp Displays help screen for commandacct method [local|radius]Displays accounting method currently in useSets accounting method to local or Radiusauth method [local|radius]Displays authentication method currently in useSet authentication method to local or Radiusbase <ipaddr> Sets base IP address for SNAPcount <1-62>Displays PPP base allocation countSet to max number of remotes parameter of radioradius help add [auth|acct]<ipaddr> [port] delete [auth|acct] <ipaddr> port [auth|acct] <ipaddr> <port-number> secret [auth|acct] <ipaddr> <secret> settingsDisplays help screen for commandAdds IP address of Radius server forauthentication or accountingDeletes IP address of Radius serverSets the port number for a Radius serverSets the secret for a Radius serverDisplays Radius servers settingsstatus Displays status of registered userstimeout <time> Sets idle time timer in tenths of secondspppuser helpadd <usr>delete <usr>disable <usr>enable <usr>listpassword <usr> <pwd>Displays help screen for commandAdds a PPP userDeletes a PPP userDisables a PPP userEnables a PPP userList current PPP users, both enabled and disabledSet PPP user passwordhelp Displays the subcommands for the PPP mode.acct Displays/sets the accounting method to be used for IP traffic. When set tolocal, the SNAP keeps track of the amount of data traffic and time used byeach user. When set to radius, the accounting information is sent to thedesignated accounting Radius server.auth Displays/sets the authentication method to be used when users sign on. Whenset to local, the password entered by the user when establishing the PPPsession must agree with the password entered for that user in the SNAP.When set to Radius, the password entered by the user is sent to thedesignated authentication Radius server.
2000 Digital Wireless Corporation 14 042000base Sets base IP address for IP addresses to be assigned to remotes when in PPPserver mode. The base address is assigned to the first remote that registerswith the SNAP. The next remote to register is assigned the base IP addressincremented by one.count Displays/sets the PPP base allocation count. This number must be equal orlarger than the maximum number of remotes the radio as it determines thenumber of buffers the SNAP will set up to assemble SNAP datagrams.radius These commands are used to set up one or more Radius servers to performauthentication and accoutning functions. Separate servers may be used foreach function.status This command displays the status for all currently registered users includingthe IP address assigned to the user, the serial number of the remote radio, thenumber of bytes and packets received and sent as well as bad packets.timeout This command allows the SNAP to terminate the PPP session of an idleremote after the specified amount of time. Time is specified in tenths ofseconds, thus a value of 600 corresponds to one minute. If the value is set tozero, the timeout feature is disabled.user Manipulates users that are entitled to connect to the SNAP. Also sets thepassword for each entered user. usr and pwd can be any alphanumeric stringup to 32 bytes in length. When a new user is added, a password must beassigned and the user must be enabled before access will be granted. Apassword must be assigned even if a Radius server is to performauthentication. There is no way to display passwords. If a password isforgotten, a new password must be entered.
2000 Digital Wireless Corporation 15 042000RADIO MODEM CONFIGURATIONThe “radio” command provides access to several sub-commands that are useful inconfiguring the WIT2410(s) in the SNAP. The format for the radio commands is radio{A|B} <sub-cmd> [<sub-cmd-args>], where the {A|B} is either of the letters ‘A’ or‘B’ used to specify to which radio the sub-command should be applied. TheSNAP2410/2414 uses only radio ‘A’ and the SNAP2420 uses both radios ‘A’ and ‘B’.The command radio {A|B} banner can be used to display the banner from the radio.This is useful in determining the unique ID of the radio and the version of firmwarerunning in the radio.The command radio {A|B} cfg gives access to the configuration mode of theWIT2410. When configuration mode is entered, the SNAP> prompt becomes just a >prompt. To exit radio configuration mode, press the ESC key on the upper left portion ofthe keyboard. The SNAP> prompt will return.Radio CommandsThe radios in the SNAP are set with factory defaults which should be sufficient for mostapplications. For other applications, the following radio commands can be used to finetune the performance of the SNAP.Command Descriptiondx [?|0-62] Set range optimizationph [?|0-fe] (base only) Sets the hop duration in 69.4us increments.90H = 10ms (default)pw [?|0-35] (base only) Set Base Slot Size35H = 212 bytes (default)wn [?|0-63] Sets the network number (hopping pattern)0 = defaultSet Range OptimizationFor ranges in excess of 0.9 miles, this command optimizes the over-the-air timing toprovide the most robust communications. The diagram below illustrates how theparameter works:where x is 10 times the number of miles (mod 64) around which the 1.5 mile range isdesired.Set Hop DurationSets the length of time the transceiver spends on each frequency channel. A smaller valuewill allow the remote to lock on to the base signal faster at startup and will generallydecrease packet latency. A larger value increases network capacity due to decreasedoverhead in channel switching. The hop duration is specified in 69.4us increments. Thex-0.6xx+0.9
2000 Digital Wireless Corporation 16 042000default value of 90H corresponds to a duration of 10ms. The maximum value of FEH is17.627ms. For best results do not specify a duration of less than 3ms. This value onlyneeds to be changed in the master SNAP radio which broadcasts the parameter to allslave device radios. However, the SNAP command hop length <hoplen> must be usedto set the new hop duration in the SNAP processor of each slave SNAP. Initial link timecan be reduced if this value is set in the slave radios which will use it as a starting valuewhen scanning for a master.Set Base Slot Size (master radio only)Sets the amount of time allocated for transmission on each hop for the SNAP radio timeslot in 69.4us increments. Each increment corresponds to 4 bytes. Maximum value is 35Hwhich corresponds to 212 bytes. This is the default value and should only be changed toprovide more throughput for the slave device(s) at the expense of the master devicethroughput.Set Network Number (hopping pattern)The radio in the SNAP has 64 preprogrammed hopping patterns or network numbers. Byusing different network numbers, nearby co-located networks can avoid interfering witheach others’ transmissions. Even if both networks tried to use the same frequency, on thenext hop they would be at different frequencies.
2000 Digital Wireless Corporation 17 042000SNAP DATAGRAM PROTOCOL (SDP)OverviewThe SNAP Datagram Protocol (SDP) is a UDP (datagram) protocol implemented in theSNAP to communicate remote radio data to and from workstations on the network. Theuse of UDP datagrams permits the SNAP to unicast, multicast, or broadcast remote radiodata to multiple workstations on the network. The SDP datagrams transmitted by theSNAP are sequenced so that a receiving workstation can detect datagrams that do not getdelivered. The SNAP caches SdpCache number of datagrams so that a receivingworkstation can request a retransmit of a particular datagram. The number of cacheddatagrams, SdpCache, defaults to eight and can be configured on the SNAP.A specific unit of information regarding the SDP or a remote radio is referred to as a“message” and are defined in detail below. Each SDP datagram consists of a header andone or more messages. The sum of the lengths of the header and all of the messageswithin the datagram will not exceed SdpMax bytes, which is a configurable parameterand defaults to 512 bytes. The SNAP builds a datagram as the messages accumulate. Asthe SNAP builds a datagram, if the next message to be added to the datagram will causethe datagram to exceed SdpMax bytes in length, the datagram currently being built istransmitted by the SNAP to all recipients. The SNAP then begins building a newdatagram with the current message. If 20 milliseconds elapse after the last message isadded to the datagram being built, then that datagram is transmitted by the SNAP to allrecipients. If there are no messages to send for 500 milliseconds after the last datagramhas been transmitted, the last datagram is retransmitted by the SNAP to all recipients. Ifthere are still no messages to send for 1 second after this, the last datagram is once againtransmitted by the SNAP to all recipients. The retransmission of the last datagram aids inthe detection of datagrams that fail to be delivered.Datagrams that are sent by workstations to the SNAP(s) have a similar format to thosesent by the SNAP to the workstations. There is currently no provision foracknowledgement or request-for-retransmit of datagrams sent by workstations to theSNAP. One of the messages that a workstation may send to a SNAP in a datagram isused to request the retransmission of a datagram. If the datagram indicated by thesequence number in the request is currently cached by the SNAP, that datagram will betransmitted by the SNAP directly to the host requesting the retransmission.SDP HeaderThe header for an SDP datagram is eight bytes long. The first four bytes are a magicnumber in network byte order which is used to identify/qualify the datagram. Whentransmitting a datagram, the SNAP places the value SDP_SNAP_MAGIC in the magicfield of the header. When receiving a datagram, the SNAP expects the valueSDP_USER_MAGIC in the magic field of the header. The next byte is the sequencenumber which increments for each datagram transmitted by the SNAP. The next threebytes of the header are the unique-ID of the “radio A” for the SNAP.
2000 Digital Wireless Corporation 18 042000#define SDP_SNAP_MAGIC (0x73647030l) /* 'sdp0' */#define SDP_USER_MAGIC (0x53445030l) /* 'SDP0' */typedef unsigned char byte;typedef struct { ulong magic; byte seq; byte base_id[3];} sdphdr_t;SDP MessagesEach “message” that is contained within an SDP datagram consists of a type byte, alength byte, and some number of parameter bytes depending upon the type of themessage. The values for the type byte are specified below. The length byte specifies thelength of the message and includes the type and length bytes. There are seven messagetypes defined for SDP:TYPE SENT-BY FunctionSDP_SM_STARTUP SNAP indicates SNAP startup / SDP initializationSDP_SM_CONNECT SNAP Remote radio has connectedSDP_SM_INPUT SNAP Data from remote radioSDP_SM_DISCONNECT SNAP Remote radio has disconnectedSDP_UM_STARTUP Workstation Indicates workstation startupSDP_UM_RESEND Workstation Requests retransmission of SDP datagramSDP_UM_OUTPUT Workstation Data for remote radioSDP_SM_STARTUPByte Value0 Type = ‘s’ (0x73)1 Length = 42 <cache> (The number of datagrams the SNAP will cache)3 <user-request>When the SNAP is powered on, it will transmit an SM_STARTUP message. The valuefor <user-request> at this time is 0. When a workstation starts-up (or an application onthe workstation which uses SDP to talk to the SNAP) it will send a UM_STARTUPmessage. At this time, the SNAP will transmit an SM_STARTUP message with a <user-request> value of 1 followed by an SM_CONNECT message for each remote radiocurrently “connected” to the SNAP. [In future releases, this will be followed by an
2000 Digital Wireless Corporation 19 042000SM_STARTUP message with a <user-request> value of 2]. This allows the workstationsoftware to become aware of remotes that are present in the network. This message willalways be the first message in an SDP datagram.SDP_SM_CONNECTByte(s)Value0 Type = ‘c’ (0x63)1 Length = 72-4 Unique-ID of remote radio5 Receive sequence number for remote radio6 Transmit sequence number for remote radioThe SM_CONNECT message is transmitted by the SNAP when each remote radioconnects to a base radio in the SNAP. This message type is also transmitted by theSNAP for each radio currently connected to the base radio(s) in the SNAP following aUM_STARTUP message from a workstation.SDP_SM_INPUTByte(s)Value0 Type = ‘i’ (0x69)1 Length = 7 + <number of data bytes>2-4 Unique-ID of remote radio5 Sequence number for data (modulo 16)6 Length of data to follow (perhaps redundant)7-N Data bytes from remote radioThe SM_INPUT message is transmitted by the SNAP to communicate remote radio datato the workstations.SDP_SM_DISCONNECTByte(s)Value0 Type = ‘d’ (0x64)1 Length = 52-4 Unique-ID of remote radioThe SM_DISCONNECT message is transmitted by the SNAP to indicate that a remoteradio has disconnected from the base radio in the SNAP. Note that the remote may havealready roamed to another SNAP. The workstation should only act on theSM_DISCONNECT message if it currently has the source of this message as the SNAPthat owns this remote radio.
2000 Digital Wireless Corporation 20 042000SDP_UM_STARTUPByte Value0 Type = ‘S’ (0x53)1 Length = 2A workstation application will transmit this message (as a unicast, broadcast, ormulticast) when it initializes, prompting the SNAPs on the network to send the currentstate of remote radios currently connected to each SNAP (i.e. an SM_STARTUP messagefollowed by SM_CONNECT messages). For multicasting UM_STARTUP messages, theworkstation should use the multicast address as set by the “sys xcast” command (see thesection above on Synchronization), as the SNAP will be receiving datagrams at thismulticast address.SDP_UM_RESENDByte Value0 Type = ‘R’ (0x52)1 Length = 32 Sequence number of datagram to retransmitA workstation will use this message to request that a SNAP retransmit an SDP datagramthat the workstation may not have received. The third byte of this message indicates thesequence number of the SDP datagram that the workstation did not receive. Theworkstation will detect that it has not received an SDP datagram when it receives adatagram out of sequence but within the window defined by the “cache” setting of theSNAP. This message should be unicast to the particular SNAP from which theworkstation has missed a datagram.SDP_UM_OUTPUTByte(s)Value0 Type = ‘O’ (0x4F)1 Length = 6 + <number of data bytes>2-4 Unique-ID of remote radio5 Number of data bytes to follow (perhaps redundant)6-N Data to be transmitted to remote radioA workstation uses the UM_OUTPUT message to send data to a remote radio. Thenumber of data bytes specified and contained in this message must not exceed the baseradio’s setting for the maximum transmit packet size. This message may be broadcast ormulticast to multiple SNAPs as the SNAP will ignore this message if the remote radiowith the Unique-ID contained in the message is not currently connected.
2000 Digital Wireless Corporation 21 042000TROUBLESHOOTINGConnect LED is not on.Check the power LED on the SNAP. Check the ethernet cable, making sure that it isfully connected. CheckCannot telnet to SNAP.Check the power LED on the SNAP. Check the ethernet cable, making sure that it isfully connected. Make sure the SNAP has a unique IP number on the network and onethat is valid for the network, ie, that can be seen through switches, hubs and routers.Cannot communicate with a remote radio.Check the list of registered remotes on the SNAP to make sure the remote is registered. Ifthe remote is not registered, check that the remote is not is sleep mode. Verify that theremote is in range of the SNAP.Technical SupportTechnical Support is available from Digital Wireless from 8:30am to 5:30pm EasternTime, Monday through Friday. Contact Technical Support at (770) 564-5540 or by emailat techsup@digiwrls.com.
2000 Digital Wireless Corporation 22 042000QUICK REFERENCESNAP System Commandsecho Toggles user screen echo modehelp Displays command help screenreset Resets the SNAP to activate new parameterssave Stores current configuration in non-volatile memorysys helpoutmax <1-212> Sets maximum transmit packet lengthmode [AP|PPP] Sets SNAP operating modexcast <b/mcastaddr> Sets SNAP multicast addressversion Displays SNAP firmware version numberEthernet Commandsarp -a Displays arp table-d <ipaddr> Deletes arp entry-s <ipaddr> <eaddr> Adds arp entryip <ipaddr> <netmask> Sets SNAP IP address and optional netmaskpassword Sets password for telnet sessionsping <ipaddr> Pings TCP/IP hostsroute helpadd <ipaddr|default> Adds IP address and netmask to route table<gwaddr> <netmask>del <ipaddr> Deletes IP address from route tablelist Lists route table IP addressessocks Diplays network socket informationSNAP Radio Commandshop helplength <hoplen> Informs SNAP of radio hop dwell timesequence <75|25> Informs SNAP of number of frequenciesradio [A|B] helpbanner Displays the banner of the specified radionetwork Displays network number of specified radiocfg Puts specified radio in configuration moderemote helplist Displays remotes currently registeredsend <hnd> <data> Sends data to the specified remotesync helpether Sets sync mode to use Ethernet packetsmaster Sets SNAP as sync masteroverride Toggles master backup overridesettings Displays sync settingsslave Sets SNAP as sync slavewire Sets sync mode to use RS-485 wire ports
2000 Digital Wireless Corporation 23 042000Radio Commandsdx [?|0-62] Sets range optimization in radioph [?|0-fe] base only Sets hop duration in 69.4s incrementspw [?|0-35] base only Sets Base Slot Size (35H=212 bytes=default)wn [?|0-63] Sets the network number (hopping pattern)AP Mode Commandssdp helpadd <sdp> <ipaddr> <dstprt> Adds an SDP entry<srcprt>cache <size> Sets the number of cached SDP output packetsdelete <sdp> Deletes an SDP entrylist Lists SDP entriesmax <size> Sets SDP maximum packet sizePPP Mode Commandsppp helpacct method [local|radius] Sets accounting method to be usedauth method [local|radius] Sets authentication method to be usedbase <ipaddr> Sets base IP address for remotescount <1-62> Set to max number of remotes pararmeter of radioradiusadd [auth|acct] Adds IP address of Radius server <ipaddr> [port]delete [auth|acct] Deletes IP address of Radius server <ipaddr>port [auth|acct] <ipaddr> <pnumber> Sets the port number for a Radius serversecret [auth|acct] <ipaddr> <secret> Sets the secret for a Radius serversettings Displays Radius server settingsstatus Displays status of registered userstimeout Sets idle time timer in tenths of a seconduser helpadd <usr> Adds a PPP usernamedelete <usr> Deletes a PPP usernamedisable <usr> Disables a PPP usernameenable <usr> Enables a PPP usernamelist <usr> Lists current PPP userspassword <usr> <pwd> Sets PPP user password
2000 Digital Wireless Corporation 24 042000WIT2410 Command SummarySerial Commandssd[?|00..ff] Set Data Rate Divisorsp[?|00..14] Set Protocol ModeNetwork Commandswb[?|0|1] Set Transceiver Modewd[?|1..3f] Set Default Handlewn[?|00..3f] Set Hopping Patternwg[?|0|1|2] Enable Global Network Modeswp[?|0|1] Set Transmit Powerwr? Read Receive Signal Strength (remote only)dx[?|0..64] Set Range Optimization (base only)Protocol Commandspe[?|0..4] Set Alternative Frequency Bandph[?|00..fe] Set Hop Duration (base only)pl? Get Maximum Data Lengthpn[?|01..3e] Set Maximum Number of Remotes (base only)pk[?|00..d4] Set Minimum Data Lengthpr[?|00..ff] Set Packet Attempts Limitpt[?|00..ff] Set Data Transmit Delay (remote only)pv[?|0|1] Set Slot Assignment Mode (base only)pw[?|00..35] Set Base Slot Size (base only)px[?|0|1] Set ARQ ModeStatus Commandszb[?|0|1] Banner Display Disablezc[?|0..2] Set Escape Sequence Modezh? Read Factory Serial Number High Bytezm? Read Factory Serial Number Middle Bytezl? Read Factory Serial Number Low Bytezp[?|0..4] Set Duty Cyclezq[?|0|1] Enable Low Power Acquisition (remote only)z> Exit Modem Control ModeMemory Commandsm0 Recall Factory Defaultsm< Recall Memorym> Store Memory
2000 Digital Wireless Corporation 25 042000SPECIFICATIONSRadio SpecificationsModel SNAP2410 SNAP2420 SNAP2414Data Throughput 230.4Kbps 460.8Kbps 230.4KbpsTotal over-the-airbandwidth 460.8Kbps 921.6Kbps 460.8KbpsNetwork Interface 10BaseTSNAP NetworkTopologies Point-to-Point or MultipointRepeater Use Digital Wireless HN-2010RF Output Power 100mW wiith included whip antenna, 400W EIRPwith gain antennaRF Modulation Frequency hopping, up to 64 user selectablehopping patternsFrequency Range 2400MHz to 2483.5MHzOperating Voltage Range 7VDC to 26VDCEnclosure Ruggedized Aluminum ABS PlasticDimensions 201 x 144 x 53 mm7.9” x 5.7” x 2.1” 210x229x45 mm8.25x9.0x1.75inOperating Temperature -30°C to +70°C0 to 95% humidity, non-condensingLicensing Type certified for Worldwide License-free operationunder FCC Part 15.247 and ETS 300.328ConnectorsPower 2-Pin DINEthernet RJ-45Configuration Port DB-9Antenna TNC MaleHub (2414 only) RJ-45IndicatorsPowerEthernet Transmit DataEthernet Receive DataEthernet Link StatusEthernet Collision
2000 Digital Wireless Corporation 26 042000WARRANTYSeller warrants solely to Buyer that the goods delivered hereunder shall be free fromdefects in materials and workmanship, when given normal, proper and intended usage, fortwelve (12) months from the date of delivery to Buyer. Seller agrees to repair or replace atits option and without cost to Buyer all defective goods sold hereunder, provided thatBuyer 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 toSeller’s plant, provided that Buyer first obtain from Seller a Return Goods Authorizationbefore any such return. Seller shall have no obligation to make repairs or replacementswhich are required by normal wear and tear, or which result, in whole or in part, fromcatastrophe, fault or negligence of Buyer, or from improper or unauthorized use of thegoods, or use of the goods in a manner for which they are not designed, or by causesexternal to the goods such as, but not limited to, power failure. No suit or action shall bebrought against Seller more than twelve (12) months after the related cause of action hasoccurred. Buyer has not relied and shall not rely on any oral representation regarding thegoods sold hereunder, and any oral representation shall not bind Seller and shall not be apart of any warranty.THE PROVISIONS OF THE FOREGOING WARRANTY ARE IN LIEU OF ANYOTHER WARRANTY, WHETHER EXPRESS OR IMPLIED, WRITTEN ORORAL (INCLUDING ANY WARRANTY OR MERCHANT ABILITY ORFITNESS FOR A PARTICULAR PURPOSE). SELLER’S LIABILITY ARISINGOUT OF THE MANUFACTURE, SALE OR SUPPLYING OF THE GOODS ORTHEIR USE OR DISPOSITION, WHETHER BASED UPON WARRANTY,CONTRACT, TORT OR OTHERWISE, SHALL NOT EXCEED THE ACTUALPURCHASE PRICE PAID BY BUYER FOR THE GOODS. IN NO EVENTSHALL SELLER BE LIABLE TO BUYER OR ANY OTHER PERSON ORENTITY FOR SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES,INCLUDING, BUT NOT LIMITED TO, LOSS OF PROFITS, LOSS OF DATA ORLOSS OF USE DAMAGES ARISING OUT OF THE MANUFACTURE, SALE ORSUPPLYING OF THE GOODS. THE FOREGOING WARRANTY EXTENDS TOBUYER ONLY AND SHALL NOT BE APPLICABLE TO ANY OTHER PERSONOR ENTITY INCLUDING, WITHOUT LIMITATION, CUSTOMERS OFBUYERS.

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