Dropping DTR to access command mode during ppp session

[Steve Lin]

Hello,

I have a need to access my modem's command mode in order to issue some AT
commands to obtain line status/quality and some other queries, DURING a
ppp session.

According to the modem manual, dropping DTR will put the modem into
command mode (while keeping the connection up, similar to doing a "+++"
but with more positive control).... then in theory I should be able to do
my AT commands, terminating with an ATO to put the modem back into data
mode.

However, there seem to be a couple problems with this:

1)  Can't seem to figure out a way to get ppp itself to drop DTR and then
allow me to use the "term" command to query the modem.

2)  If I write an external program to drop DTR, I suspect ppp will get
VERY confused...

I've seen mention of the desire to do something similar in the list
archives but no actual successful ways of doing it.

Any ideas on how to be able to issue AT commands to my modem during a ppp
session?

Thanks!!
Steve Lin