...Connection problem with modem...



I am not able to establish a connection (AT commands included) between my fastrack modem and computer thru its serial port.

Here is a behavior that may give some insights for troubleshooting ideas:

  • When I power the modem, the red led gets turned on
  • As soon as I connect the modem to the serial port, the red led gets turned off.

Any creative ideas?



When you power the unit up (with SIM inserted & antenna connected), the red LED should come on steady;
Then, after a few seconds, it should start blinking.

Does this happen if you just power-up the unit and don’t connect it to the PC?

How, exactly, are you connecting to the PC?



I got same problem. I plug the device into the power and wait for a while but the led still continuously be red (not blinking). Then i plug it to my computer and the led turn off right away.

Pls help.


If I just power-up the unit and don’t connect it to the PC, the red LED comes on steady. Then it blinks every about 5 seconds.

When I connect it to my PC (through its serial port), the red LED turns off right away, and never comes back on.

It looks like “naked kid” has got a similar problem.

Any idea?


Hello, here’s one:

The first time I experienced that problem was due to a wrong cable.

I was experiencing the same problem today with a proper cable.
The problem vanished when I disconnected the ring indicator wire (pin 13 of the DB15 connector).
I also suspect that Windows hyperterminal has something to do with it, but have no definitive proof yet.


Sorry, I made another wiring mistake, I was using pin 15 as 13. It comes clear that a wrong cable makes the modem go crazy.


Remember that the 15-pin connector includes a BOOT pin and a RESET pin - if you wire them incorrectly, you most certainly will make the modem go crazy…!! :open_mouth: :open_mouth:


Thanks. I checked my 15-pin to 9-pin adaptor I had bought in a store and the wiring is not the one required for the modem.

Out of curiosity, where did you buy your adaptor. I have a hard time to find one on the web. Any help will be much appreciated!!


Did it claim to be an adaptor for a Wavecom modem?
If it didn’t say that, there was absolutely no reason whatsoever to assume that it would work! :unamused:

It was included in the Kit with the modem.
And the pinout is provided in the manual for the modem.

Anywhere selling the modems should have the cables, surely? :open_mouth:


Thanks! With the proper cable, the modem and the computer can now talk to each other. The AT command works; however, I am not able to initiate a call or send an SMS.

Here are some experienced behaviors:
A) AT+CSQ -> Answer: +CSQ: 15,0
B) The red LED is consistently on (no flashing)
C) All of the AT+COPS commands return “ERROR”
D) After AT+CPIN=xxxx, AT+CPIN? returns +CPIN: READY. After a few seconds, I get a +WIND: 3 and a +WIND: 1. Afterwards, AT+CPIN? returns +CPIN: SIM PIN… like if the PIN had to be sent again.

My configuration:
Wavecom Fastrack M1213A (900 / 1900 MHz)
Cingular SIM Card
Location: United States

Any thoughts?