RV-M50-E Technical Manual
15
5.
Troubleshooting
5.1.
Symptom: Unit will not receive
Solution #1: Verify that the unit is on the correct RF channel. If it is, the Status LED should blink green
every time another modem tries to transmit to it. If the Status LED does not blink when it should be
receiving, it is on the wrong RF frequency.
Solution #2: If the Status LED blinks green, 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 and
spreading factor of all modems is the same (ATSF command).
Solution #3: Verify the KEYPHRASE is correct. If encryption is used, the KEYPHRASE is set to a unique
word, and must be the same in all radios in the system. If it is not used in the radio system, then the
KEYPHRASE in all units must be disabled or left at the factory default. To disable encryption, use the
KEYPHRASE 0 command. The factory default KEYPHRASE is RAVEON, in all capital letters.
Solution #4: Verify the Receiver circuits are powered. The receiver circuitry by default is disabled (ATSM
4). If you wish to receive data with the modem, you must enable the receiver circuits, increasing the
current draw a little bit. ATSM 0 enables the receiver circuits.
5.2.
Symptom: Receive light blinks, but no data is received
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 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: Verify the KEYPHRASE is correct. If encryption is used, the KEYPHRASE is set to a unique
word, and must be the same in all radios in the system. If it is not used in the radio system, then the
KEYPHRASE in all units must be disabled or left at the factory default. To disable encryption, use the
KEYPHRASE 0 command. The factory default KEYPHRASE is RAVEON, in all capitol letters.
5.3.
Symptom: Long delay before transmitting
Solution #1: Verify that serial port timeout is OK. The ATR3 command sets the number of milliseconds
that the modem 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).
5.4.
Symptom: Cannot enter Command Mode
Solution #1: Verify the serial port baud rate. This is difficult if it is set wrong, because you cannot enter
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
