Company Confidential
40
Raveon Technologies Corp.
12. Troubleshooting
Symptom: Unit will not receive
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
M8T
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
M8T
modem, using the
ATCH 0
command.
Solution #3
.
If the status RX LED blinks green when a different unit transmits, 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 M8T has an optional Low Power Mode (LPM). If
LPM is enabled, the M8T 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 M8T 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: Unit will not transmit
Solution #1
.
Verify that CTS is wired. Some devices that could be connected to the
M8T
will
require the CTS signal to be asserted. The
M8T
does assert this signal, but if the wire is not
connected, you device may not be outputting data to the
M8
. If the TX LED blinks, the
M8T
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
M8T
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 0
command 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 M8T has an optional Low Power Mode (LPM). If
LPM is enabled, the M8T 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 M8T 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: Receive light blinks, but no data is received
Solution #1
.
Verify Input/Output Configuration. The
M8T
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
