Am 07.03.2016 um 07:57 schrieb Holger Schurig:
> I know that in Germany a good amount of land-line telephone line are
> still using ISDN. [...]
> Especially company line are using ISDN still, and there are some Linux
> programs that act on then, e.g. Asterisk and derived PBX software has
> ISDN support which is actively used.

AFAIK none of these uses I4L anymore. Asterisk dropped I4L support with
version 2 if my memory is correct and nowadays uses CAPI, mISDN or its
own DAHDI interface.

-- 
Tilman Schmidt                              E-Mail: tilman@imap.cc
Bonn, Germany
Nous, on a des fleurs et des bougies pour nous protéger.