Re: ISDN CHANNEL-D

[Sam Ravnborg]

On Wed, Jan 16, 2002 at 08:58:02PM +0000, Padraig Brady wrote:
> AstinusLists wrote:
> 
> > Hello every one.
> > 
> > I've been earing some rumors, that i am quite sure that are turth about the
> > isdn channel d.
> > 
> > As all of u know ( i think ) isdn cards have 3 channels: 2*64 and one time
> > 16 kbs.
> > 
> > This last one is called channel D.
> > Channel D is used to dial and to reply to tones and minor stuff like that.
> 
> Yes info is passed across the D channel in messages. There is a message
> 
> type called User User information that can be passed, but only with and
> associated D channel call type, i.e. you must pay for it.

What the original author refer to is utilising the D-Channel to support
LAPB/X.25 traffic. This is done using a special SAPI=16 value.
I dunno if the ISDN drivers in Linux support this yet.

Charging for the above is operator specific, when I worked with this in the past
the charging was unrealistic high.

	Sam