> On Fri, 11 Apr 1997, Joe Portman wrote:
>
> > On Fri, 11 Apr 1997, ServNet Listbox - wrote:
> >
> >
> > I'm going to take a WAG here. V.120 is commonly an ISDN only protocol.
> > Since the call coming in is not a true ISDN call, the V.120 code doesn't
> > get kicked in.
> >
>
> It is too an ISDN call. Have you forgotten what the 'I' stands for?
Yup. I know what the ISDN stands for. Now, if you have ISDN on both the
calling and terminating equipment, then it is an ISDN call.
If you do not, then it is not. It is a 'hybrid' call. The call is
initiated using ISDN with the VOICE attribute set (just as if you had
picked up the handset).
The receiving end (a channelized T1) can only receive VOICE calls. But, it
can make a 56K "ersatz" digital call by bypassing the modem codec and
talking straight HDLC. So it's really a LOT more like switched 56K than it
is ISDN, but that's just my (and my 20+ years telco experience) talking.
It is in no sense a fully ISDN call, since there is NO D CHANNEL to handle
the call setup and teardown.
Cordially,
-----------------------------------------------------------------------------
Joe Portman - Alternate Access Inc. Affordable, Reliable Internet
-----------------------------------------------------------------------------