• pppd-at

Using AT Commands on an Active pppd Session

After tinkering with my wmii scripts to display a number of useful things in the status bar when I had completed my wireless network monitoring script I decided it would be really neat to have a mobile phone modem monitoring script for when I'm connecting to the Internet via GPRS/3G. This could easily be done by sending AT commands to the mobile, the tricky part doing this on an active link.

I quickly found that annoyingly there were some realy nasty limitations with my shiny Symbian based SE P1i:

• the phone does not support Bluetooth NAP networking, it only does GN. This means the phone cannot act as a router for my laptop to the Internet
• Many other phones supply multiple virtual Bluetooth provisioned serial ports which would mean I could run pppd on one of those channels and then use another serial port to monitor the signal level. Of course the SE P1i does not support this feature...

Digging around the Internet I stmbled on a couple of relevant postings and it looks like someone (I guess that person is now going to be me) has to patch the kernel and pppd to permit this dropping to command mode functionality. This page details my slow progress.

Links

• Other People Wanting This Feature:

  • switching to command mode when using a PPPD with a gprs modem - pppd feature request

  • command mode and GPRS at the same time

• The 'AT+CSQ' Command:

  • AT+CSQ (Signal Quality Measurement)

  • AT+CSQ Signal Quality