AT command interface

[James Skinner]

I wanted to try to send some AT commands outlined in the AT manual? Looking for a good way to do this?

Ideally, I would like to send the AT commands from a Java program while PPP is up and running, but don’t see any java classes to support this.

Thanks in advance,

James

[Jesse Gilles]

Depending on the CDP model you have, sending AT commands while PPP is running may not be possible. The MTCDP-E1, MTCDP-G2 and MTCDP-EV2 only provide one serial port device that takes AT commands, so if PPP is running, the port is in use.

The MTCDP-H4 (HSPA) does provide numerous serial device ports, which allows you to use one for PPP and use others for AT commands while simultaneously.

http://www.multitech.net/developer/products/cellular-development-platform/hardware/accessing-hardware-interfaces/

As far as reading/writing to the serial port from Java, I can’t give specific advice, but I assume it will be similar to other languages running in Linux. The serial device port is treated as a regular file and you can do read/write IO operations on it to send commands and read back the response.

[James Skinner]

Thanks, I have the new MTCDP-H4 (HSPA) and was able to enter AT commands using microcom. I did notice though AT+CSQ and ATI returned the values that I was expecting but was not able to get other commnads such as AT!GSTATUS? and AT!GSMINFO? to return anything but OK. Any idea why?

[Jesse Gilles]

Which tty port are you running the commands on? Only /dev/ttyUSB3 supports the full AT command set. If you need access to the full AT command set, it is recommended that you initiate your PPP link on /dev/ttyUSB4 which leaves USB3 open for other use.

This is mentioned as a note on the “Accessing Hardware Interfaces” page: http://www.multitech.net/developer/products/cellular-development-platform/hardware/accessing-hardware-interfaces/

[Author]

Posts