RV-M7 Data Radio Modem Technical Manual
- General Information and Overview
- Specifications
- Electrical Inputs and Outputs
- Serial Port Commands
- Using the M7 Modem – Packet Mode
- Using the M7 Modem – Streaming Mode
- Installation
- FCC Licensing Information
- M7 Diagnostic Provisions
- Tuneup and Alignment
- Skyline Compatibility
- Antenna Information
- Appendix A. Serial Port Hardware
- Troubleshooting
- Mechanical Information
Solutions by Industry
RV-M7 Data Radio Modem Technical Manual
Troubleshooting
Solution #1. Verify that the modem is on the correct RF channel. If it is, the RX LED should blink every time another modem tries to transmit to it. If the RX LED does not blink when it should be receiving, it is on the wrong RF frequency.
Soultion #2. If the addresses match, and RX LED blinks but still no reception of data, verify that the RTS signal is asserted. The M7 will not output data if the RTS signal on the DB-9 I/O connector is not asserted. If the user’s hardware cannot assert the RTS hardware line, disable hardware flow control in the M7 modem, using the ATCH 0 command.
Solution #3. If the RX LED blinks, verify that the Unit Address of the sending modem matches the unit address of the receiving modem. If this is OK, verify that the over-the-air baud rate of all modems is the same (ATR2 command).
Solution #4. Verify Low Power Mode. The M7 has an optional Low Power Mode (LPM). If LPM is enabled, the M7 will power down whenever the DTR line of the serial port is turned off. The Power LED will blink once every 10 seconds in the LPM mode. The ATSM command is used to set or read the Low Power Mode. ATSM 1 enables it, and ATSM 0 disables it. If LPM is used (ATSM 1), then the M7 will turn off when the DTR line is off, or the program connected to the serial port is closed, or the RS-232 connector is un plugged.
Solution #1. Verify that CTS is wired. Some devices that could be connected to the M7 will require the CTS signal to be asserted. The M7 does assert this signal, but if the wire is not connected, you device may not be outputting data to the M7. If the TX LED blinks, the M7 is transmitting data. Every time data enters the modem, the TX LED should blink
Solution #2. Verify that serial port timeout is OK. The ATG0 command sets the number of microseconds that the M7 will look for in the serial input data stream. If a pause greater than this value happens, the modem will transmit. If the ATG0 paramter is set very large, say 2000000, this means 2 seconds, and the modem may simply be waiting a long time
Solution #3. Verify that the radio channel is clear or BCL is off. The ATBC 1 command enables Busy Channel Lockout. If BCL is on, the modem will not transmit on a busy channel. The ATBC 0command turns it off, and thus the modem will transmit when it needs to, regardless if the channel is busy. The RX led on the front of the modem is illuminated whenever the radio channel is busy (RF present).
Solution #4. Verify Low Power Mode. The M7 has an optional Low Power Mode (LPM). If LPM is enabled, the M7 will power down whenever the DTR line of the serial port is turned off. The Power LED will blink once every 10 seconds in the LPM mode. The ATSM command is used to set or read the Low Power Mode. ATSM 1 enables it, and ATSM 0 disables it. If LPM is used (ATSM 1), then the M7 will turn off when the DTR line is off, or the program connected to the serial port is closed, or the RS-232 connector is un plugged.
Solution #1. Verify Input/Output Configuration. The M7 has numerous I/O options. RS232 is standard, but Ethernet, RS485 or RS422 may be configured also. Use the ATIO command to view how the I/O is configured. ATIO 0 is the default (RS232 mode).
Solution #2. Verify the serial port baud rate. This is difficult if it is set wrong, because you cannot enter the command mode to check it. Try all possible baud rates, and see if one of them works with the modem. Alternately, remove the rear cover of the modem, and press the CONFIG button. This will force the modem into the Command Mode, as well as set the serial port to 9600 baud, 8 data bits, one stop, and no parity. If the baud-rate was OK, verify the AT, BT and CT times, that they are long enough for you to enter the +++ string.
Solution #1. Verify that serial port timeout is OK. The ATR3 command sets the number of milliseconds that the M7 will look for in the serial input data stream. If a pause greater than this value happens, the modem will transmit. If the ATG0 parameter is set very large, say 2000, this means 2 seconds, and the modem may simply be waiting a long time. Typical settings for this parameter are 20 (20mS).
Solution #1. Issue an ATSV command. After any parameter is modified, the modem will operate with the new setting, but unless the ATSV command is issued, it will revert to the old setting upon turning power off and back on again. The ATSV command saves all parameters into EEPROM memory, and these saved parameters are restored upon power up.
Solution #1. Verify the serial port baud rate. This is difficult if it is set wrong, because you cannot enter the command mode to check it. Try all possible baud rates, and see if one of them works with the modem. Alternately, remove the rear cover of the modem, and press the CONFIG button. This will force the modem into the Command Mode, as well as set the serial port to 9600 baud, 8 data bits, one stop, and no parity. If the baud-rate was OK, verify the AT, BT and CT times, that they are long enough for you to enter the +++ string.
Solution #2. Handshaking. You may have hardware handshaking enabled on your terminal program, but the hardware or cable may not support it. Disable hardware handshaking on your terminal program to verify this is the issue.
Solution #1. Verify the power is on. When the modem has good DC power, the PWR LED will blink once per second. If it is not blinking, either the modem does not have power, the modem is broken, or the LEDs have been disabled via the ATL0 command.
Solution #2. Verify the internal fuse OK. There is an internal fuse in the RV-M7, protecting it from reverse-voltage and electrical failures. If the power LED does not blink or come on when DC is applied, check the fuse and replace it with the same type 3-amp mini fuse, and try again. If you replace the fuse, the unit must be carefully check for damage and proper operation before being installed. If you replace the fuse, you must use a Littlefuse brand fuse, part number 0297003 or Raveon part, number 1X726-3 to maintain calibration of your unit.
Solution #3. Verify Low Power Mode. The M7 has an optional Low Power Mode (LPM). If LPM is enabled, the M7 will power down whenever the DTR line of the serial port is turned off. The Power LED will blink once every 10 seconds in the LPM mode. The ATSM command is used to set or read the Low Power Mode. ATSM 1 enables it, and ATSM 0 disables it. If LPM is used (ATSM 1), then the M7 will turn off when the DTR line is off, or the program connected to the serial port is closed, or the RS-232 connector is un plugged.
Symptom: Repeater will not repeat.
Solution #1. Verify the repeater’s Unit ID is unique. An RV-M7 configured to be a repeater will not repeat messages it originated. If other units in the system have the same ID as the repeater, the repeater will not repeat them because it thinks the it originated the transmission. Set the MTID of the repeater to a unique ID number.
