RV-M7 GX GPS Transponder Quick-Start Guide

8. Setup and Initial Configuration

  1. Connect a DC power source to the DC IN connection on the front of the modem. 
  2. Connect a good quality antenna, cut to the operating frequency, to the BNC connector on the front of the modem.
  3. Connect a computer terminal, or PC computer running HyperTerminal, to the 9-pin I/O connector.  The factory default serial ports settings are 4800 bps, 8 data bits, 1 stop, no parity.
  4. Put the M7 GX into the command mode.  (enter +++ per Section 0)
  5. Program the GPS mode. See the table on Page 4 to identify the mode to use, and set it with the GPS x command.  Type GX and press enter to see an overview of the current GPS related features and configuration. For in-vehicle transponders that do not connect to PCs or displays, it is usually GPS 1 mode.  For M7’s connected to a PC running RavTrack PC software, it is set to GPS 2.
  6. Program the modem’s operating frequency to your desired operating frequency.  This is done with the ATFX xxx.xxxxx command.
  7. Program the ID in the unit.  Sequentially number the M7 GX units in your system, starting with 1.  Use the ATMY command to set the ID.
  8. Program the ID to which this unit will send its data to. Typically this is the ID of the “Base” unit.
  9. Program the SLOTNUM.  This is the TDMA slot number that this unit will transmit in.  By default it is the same as its ID. Important! All radios in your system must use different SLOTNUM settings. 
  10. ATMK The network address mask. Default is F000.  This means this unit will receive all transmissions from any other unit with an ID beginning with 0 (0001 thru 0999).
  11. KEYPHRASE Enter a security key code “keyphrase”. Use any word or phrase 1-16 characters long.  It is case-sensitive.  DO NOT FORGET WHAT YOU SET IT TO!  The KEYPHRASE is the only parameter that cannot be read out of the M7 GX.  It must be the same as the KEYPHRASE programmed into all the other M7 GX transponders in your system.  The factory default KEYPHRASE is RAVEON, call capitols.
  12. To see an overview of how the modem is configured, use the SHOW command.  To see an overview of how the GPS features are configured, use the GX command.
  13. Verify the SLOTTIME and TDMATIME are set appropriate for your system.  Consult the user manual if you are not sure.  The defaults are 200mS SLOTTIME and 10 second TDMATIME, which will give you 50 slots (numbered 0-49) to track 49 transponders. 
  14. Once the unit is configured, type EXIT to exit the command mode.

Remember, that from the factory, all M7 GX GPS transponders are configured to simply work.  Plug in power and they will lock onto the GPS satellite signal and begin transmitting their positions and status in their appropriate time slot. 

    1. Enabling Repeater Features

Refer to the technical manual for advanced repeater configuration instructions.  To quickly enable repeating of all data sent from/to units 1-999, use the REPEAT 1 command.  This will enable the repeater function, and configure it to repeat messages, position, and status transmissions. 

    1. Set the Transmission Report rate

Use the TXRATE xx command to set the report rate, in seconds, for the M7 GX transponder.   For example, if you wish the M7 to report every 5 minutes, set the report rate to 300 seconds (TXRATE 300). 

If the M7 GX should report position and status when it is moving, set the TXRATE xx to the desired time between position transmissions.  Then, program the IDLERATE xx to the desired number of seconds between reports when the unit is not moving (idle). 

Important!:  Set the minimum distance the unit must move for a transmission occur with the TRIGDX xx command.   If TRIGDX is set to zero, then the unit will always report at the interval set with the TXRATE xx command. This is the factory default setting.

For example, to transmit every 2 minutes when idle, and every 10 seconds when moving more than 500 meters, use these commands:

    IDLERATE 120 (to set the idling update interval to 2 minutes.)

    TRIGDX 500 (tells it to report at the IDLERATE if it does not move this many meters)

        TXRATE 10 (configures it to report every 10 seconds whenever it is moves more than TRIGDX meters)

    1. Device Addressing

Security Key

The security KEY programmed into every M7 GX transponder ensures that only M7 GX transponders with the exact same security code can receive position and status information.  The security key is case sensitive, so “Raveon” and “RAVEON” are two different keys.  The factory default is “RAVEON”.

Addressing Basics

Addressing is used to differentiate one M7 Transponder from another.  Each must have a unique ID number programmed into them, so that when a position report is received, the ID of the M7 GX that sent the message is known.  This is called the MYID. 

Each M7 GX has an ID programmed into it, and is represented as a 4 digit number.  M7 GX IDs may be any number between 0001 and 9999.   The unit’s own ID is programmed with the ATMY xxxx command, and the ID of the destination modem it sends its messages to (the Destination Address) is configured with the ATDT xxxx command. 

The default Address Mask is F000, which means the M7 GX will receive a transmission from any other M7 as long as the fist digit matches, in this case, is a 0. 

For example, to set the MYID of your M7 to 17, enter:

    MYID 17 <enter>

To set your M7 to send its position and status data to M7 number 1, enter:

    ATDT 1 <enter>

To receive all messages from units with IDs 1-999, and exclude 1000-9999, set the mask to:

    ATMK F000 <enter>

    1. Time Slots

For optimum efficiency in a M7 GX system, begin sequentially numbering the MYID of the M7 GX transponders at ID 0001.  The second M7 should be ID 0002, and so on. 

The M7 GX transponders have internal clocks with 20 ticks-per-second.  They can measure time and initiate transmissions 20 times every second (every 50mS).  The factory default allocation is each TDMA time slot is 200mS long, and thus in 10 seconds, up to 49 M7 GX transponders may report position.  These parameters are programmable, and may be re-configured based upon the type of system they are used in. Program the slot time with the SLOTTIME xxx command, where xxx is in milliseconds.

For over-the-air rates of 4800 baud, Raveon Suggests using a SLOTTIME of 200mS when using a repeater, or 100mS if there is no repeater in the system. 

For over-the-air rates of 9600 baud, Raveon Suggests using a SLOTTIME of 150mS when using a repeater, or 50mS if there is no repeater in the system. 

A TDMA “Frame” time is the time it takes all units in your system to transmit.  This is configured with the TDMATIME xx command.  The factory default is 10 seconds, so every 10 seconds, each M7 GX is allocated a time-slot that it may use to transmit position in.  The TDMA frame must be set long enough for all units to transmit. For example, if you have 199 M7s, and use 200mS TDMA slots, then the TDMATIME should be set to 40 seconds. 

All TDMA frames are synchronized automatically in all M7 GX Transponders to the top of the minute.  Slot 0, frame 0 is at the top of each minute. Slot number 0 is used for future protocol options, and should not be assigned to any unit.


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