Maurizio Caloro <mauric@gmx.ch> writes:

> Hello
[skip]
> 164# /etc/ppp/cat ppp.log
> Serial connection established.
> Using interface ppp0
> Connect: ppp0 <--> /dev/tty00
> sent [LCP ConfReq id=0x1 <asyncmap 0x0> <magic 0x78e92f10> <pcomp> <accomp>]
> Modem hangup
> Connection terminated.

Tweak the chat script and turn on debug in its options (chat(8) -vVsS
or appropriate). I saw this issue if ISP wants to use hardware
error correction/compression, and drops connection if it did not get
this mode. This is logical issue, talk to ISP's sysadmin for details.
If it's your own project, reread modem's manual about default required
protocol features.

> best regards
> Maurizio

HTH,
-- 
= Alexey G. Khramkov (agkhram) @ Infotech <agkhram{at}mercdev{dot}com> =
= GPG fingerprint : 944D 0C8B 343B 6C8D 50A1  061A E2DA 3E11 7765 6B47 =