Sierra Wireless DART 300 User Manual

Page of 137
References 
 
DART 300 Modem 
 
Page 120 
 
2110212 Rev 1.0 
13.3. General Modem Problems 
Problem Description 
Suggestions 
Modem fails when 
transmitting. 
The LED indicator does not 
light. 
Check that the power source has adequate voltage and current.  The 
modem requires up to 1 Amp of regulated 12 V DC power.  If the power 
is marginal it can be the problem.  The power output is a function of the 
modem’s distance from the Mobile Data Base Station.  It is possible for 
the modem to work well with a particular power supply in a location 
requiring low power output (low current draw), and yet to fail using the 
same power supply in a location requiring a high power output. 
Check the amperage rating of the power supply to verify that it is 
adequate for all situations. 
Check the fuse (if any) in the power source and as a final test use a 
voltmeter to check for an open cable. 
Fails to respond to AT 
commands. 
Verify that you are using the correct COM port and communication 
parameters (speed, data bits, parity, etc.) 
Verify the serial cable connections and cable type (DTE-DCE or null-
modem), and that hardware flow control is enabled (or RTS and DTR 
are asserted). 
Power cycle the modem.  Verify the modem is powered on and allow 
for 10 seconds initialization time. 
If Auto-dial on Start-up has been set, try issuing the escape sequence 
(TIES or TDES) or toggling DTR, to return to the AT command 
processor. 
Enter the command ATE1Q0.  This will enable the modem to echo 
your keystrokes and disable the quiet mode (suppression of return 
codes). 
Enter the command AT&F.  This restores factory defaults. 
AT commands are sent to 
configure the modem but the 
modem does not use the 
settings when running an 
application. 
Ensure you have saved the configuration using &W.  Following this, 
issue Z (reset) and check the settings. 
Verify that the application does not send its own modem setup 
commands after you have configured the modem.  If it does, then either 
disable the feature or set your DART 300 configuration within the 
application’s setup string. 
Modem reports NO RADIO 
ERROR (#). 
Reset or power-cycle the modem.  If the problem persists contact Sierra 
Wireless technical support.