Date: Thu, 3 Sep 1998 22:48:45 +0200 From: Leo Weppelman <leo@wau.mis.ah.nl> To: Torsten Blum <torstenb@vmunix.org> Cc: freebsd-isdn@FreeBSD.ORG Subject: Re: called-back, rejects and auto hangup Message-ID: <19980903224845.15992@wau.mis.ah.nl> In-Reply-To: <m0zEeUH-00069xC@onizuka.vmunix.org> from "Torsten Blum" on 1998/09/03 20:52 %2B0200 References: <19980902220352.22500@wau.mis.ah.nl> <19980903162118.27170@wau.mis.ah.nl> <m0zEeUH-00069xC@onizuka.vmunix.org>
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On Thu 03 Sep 1998, Torsten Blum wrote:
> In freebsd-isdn you write:
>
> >> I think Gary said it already: the remote calls back almost immediately; long
> >> before the local call to the remote is disconnected - this can be seen
> >> from the traces you sent me in private mail.
>
> >Can you tell me why you think this is the case?
>
> There are point-to-point and point-to-multipoint isdn lines.
> (the German Telekom calls them "Anlagenanschluss" and "Mehrgeraeteanschluss")
> The first one only supports one ISDN terminal equipment (phone, router, TA,
> isdn card etc) while a point-to-multipoint line supports up to 8 TE's.
>From what I know, the machine at work is directly connected to a dutch telecom
(PTT) connection. We have one main-number & 4 MSN's. Is this multi-point?
> When a incomming call is arrives on a isdn point-to-multipoint line, all
> connected ISDN TE's are informed about the call. When an TE rejects the
> call ("call rejected", "user busy" etc) it's still possible for other TE's
> to accept the call. So the isdn switch has to wait till all remaining
> TE's signalled the switch wether they want to accept the call or not. If there's
> no response from the other TE's, the call will be rejected.
The makes me think multipoint is most common. At home I have an A/B adapter
connected to the NT1 (modem & cheapo phone) and my Atari with Teles...
> >> The only help for this situation is, to delay the callback from the remote
> >> for a time it takes to disconnect the local to the remote.
>
> No, this is not the only help, it's not even acceptable - IMHO.
> ISDN equipment that supports "ISDN callback" has to life with those call
> collisions.
But shouldn't at least one channel be free for such a collision to happen?
I mean, When I'm working on my atari through the A/B -> modem connection
to test the dialback (I tried this this afternoon ;-). The logs seem to
prove this case! At home no incoming calls before the looooong awaited
disconnect and at work all 'number busy's.
So Torsten's reasoning makes another point for being able to hangup the
phone early!
Leo.
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