Subject: Re: ISDN
To: None <>
From: Martin Husemann <>
List: current-users
Date: 07/14/1995 09:51:16
> CAPI is the defacto standard for talking to ISDN hardware in Germany, almost
> every manufacturer of ISDN boards has a CAPI driver (for DOS) available. Specs
> for implementing CAPI exists for DOS/Windows/Unix, unfortunately the Unix
> specs seem to require STREAMS.

No, they don't! The exact wording is just something between "plain wrong"
and "very Sys V'ish" - they require a cloning master device /dev/capi20
(for version 2.0 of CAPI) which clones on assignment of a B-channel during
protocol initialization, so all available B-channels and the D-channel are
accessed through a single device.

All implementations for UNIX I know of do use STREAMS (that's how Linux
got STREAMS, the ISDN driver was there first).

We can implement ISDN without streams, just a few function pointers...
[The ISDN stack consist of a quite constant number of layers, you have
few alternatives for every layers protocol, and sometimes layers use a
null protocol (called TRANSPARENT), so you don't need a free configurable
stack of STREAMS modules]