Problem sending AT commands


#1

Hi,

I am trying to send AT commands to the WP8548 but having problems. Whenever I use a + inside my command I get weird results.

The ATI command works fine:

echo ATI > /dev/ttyUSB3

Manufacturer: Sierra Wireless, Incorporated
Model: WP8548
Revision: SWI9X15Y_07.11.22.00 r33729 CARMD-EV-FRMWR1 2017/01/11 18:04:06
MEID: 35937706016152
ESN: 12812475881, 80BE5DE9
IMEI: 359377060161527
IMEI SV: 43
FSN: LL731400171610
+GCAP: +CGSM,+DS,+ES

However, when I do this:
AT+CPOF > /dev/ttyUSB3

I get:

AT+CPOF
ERROR
AT+C
ERROR
AT+C
ERROR
AT+C
ERROR
AT+C
ERROR
AT+C
ERROR
AT+C
ERROR

I am very new to the Sierra Wireless modem and using AT commands. Can someone please tell me what I am doing wrong?


#2

Hi,

What OS are you using (assuming Linux given the naming of the port)? Why are you not using a terminal program (i.e. teraterm on Windows, mincom on Linux, etc)? Also try /dev/ttyUSB2.

Regards

Matt


#3

I am using Linux.

I can’t use minicom because my target platform (an IMX7 processor) doesn’t have it. Also, I have to write to the ttyUSB device within my program using a file descriptor; I can’t use minicom.

I tried /dev/ttyUSB2 but I get similar results. It seems like the + character is an issue.