I looked at the ppp chat source and it uses
putchar to write to the device. When PPP is run over a line discipline like
n_gsm, which multiplexes a tty via the GSM 07.10 protocol, a lot of extra data is created on the link.
Can I use
stty or some other feature to glob data together? For example, if the chat script has AT\n, the following may be sent to the serial port (with
f9 07 ef 03 41 d4 f9 ....A.. f9 07 ef 03 54 d4 f9 ....T.. f9 07 ef 03 0d d4 f9 .......
The extra characters are the
n_gsm framing to a particular virtual serial port. I would prefer,
f9 07 ef 07 41 54 0d xx f9 ....AT...
Reducing the traffic from 21 characters to 9 (and I haven't included acknowledgements). The AT GPRS question has some information related to this question.
What I am asking could also be achieve by altering ppp's
chat to use
strchr('\') and using
write() instead of
putchar. I am hoping there is some
stty command turn on a Nagle like algorithm for a TTY.