On Tue, Dec 26, 2006 at 03:53:05AM +0100, Matthias Ferdinand wrote:

...
> Dec 26 03:14:00 shlab pppd[173]: Modem hangup
> Dec 26 03:14:00 shlab pppd[173]: Connection terminated.
> Dec 26 03:14:02 shlab pppd[173]: Exit.
> 
> Immediately after "Serial connection established", pppd says "Modem 
> hangup".
[...]
> pppd options I tried (without any difference)
>  - nocrtscts
>  - crtscts
>  - cdtrcts
>  - nocdtrcts
>  - crtscts nocdtrcts
>  - nocrtscts cdtrcts
>  - none of these settings

Those probably aren't relevant.

>  - passive

This would even be harmful, if the other side is "passive" too, as in
this case none of you would initiate negotiations, and one of you would
eventually time out and hang up.

What you did NOT try is:

not to use "modem", but to use

local

(which ignores the carrier detect line).

Please do.

Regards.
	-is