Ascend Archive
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

(ASCEND) DOV ISDN (fwd)

Once upon a time Laurent Saehyun Kim shaped the electrons to say...
>I've been hearing about DOV (Data Over Voice) ISDN.  Can someone enlighten
>me on this?  Do Ascend products support this?  (Especially Max series)

More properly DOSBS - Data Over Speech Bearer Service.

ISDN has two major call types (yes I'm simplifying) DATA or VOICE.  Both
can be 56K or 64K.  Now that you know there is 64K VOICE promptly forget
about it, it is very rarely used and most TAs don't support it anyway.

Ok, so you have 56K/64K DATA and 56K VOICE.  Now, in some areas (Bell
Atlantic in MA for example, where I am now) ISDN DATA calls are tarriffed
with a per minute charge.  Leaving 2 lines of DATA nailed up 24x7 would
result in a bill well in excess of $1000 a month, closer to $2000 I believe.

However, ISDN VOICE calls are NOT tarriffed per minute.  If it is a local
call, which the POP I use is, then I can pay the standard monthly line
charge of $30 or so and have two lines nailed up 24x7 (and I do).  DOSBS
is a way of running a data connection over a call that has been signalled
to the telco as a voice link.

The Ascend MAX does handle this, but you need two phone numbers if you are
also doing modems.  One number is then used for ISDN DATA and ISDN DOSBS and
the other number is used for the modems.  There are some NASes that will
do all on one number - the Lucent PortMaster-3, Bay Networks RAC8000 and
5399, and some OsiCom units are the ones I know of.  They'll do ISDN DATA,
ISDN DOSBS, and modems over one phone number on PRI.

Another nice thing is that CT1 lines are voice circuits.  It is possible
to take a 56K ISDN DOSBS call inbound over a CT1.  Technically it is also
possible to take a 56K ISDN DATA call over a CT1.  However, as CT1 circuits
are almost always labeled as a VOICE carrier, few telcos will allow this to
happen as a DATA typed call mandates an end-to-end DATA circuit.

An Ascend MAX can take ISDN DOSBS *or* modems over a CT1.  However, it cannot
take both over the same CT1 channels at the same time.  The units I mentioned
above can handle both ISDN DOSBS and modems over the same CT1, same phone
number.  (The Bay units were reported to me, the other two I've had 
confirmed by users. (Well, I worked for Lucent so I've used PM-3s to do it.))

I'm sure Kevin or Matt will correct me if I goofed on the MAX info - I'm
not sure if the new MAX6000 changes the behavior at all.

-MZ
-- 
<URL:mailto:megazone@megazone.org> Gweep, author, webmaster, human being, me
"A little nonsense now and then, is relished by the wisest men" 781-788-0130
<URL:mailto:megazone@gweep.net> <URL:http://www.megazone.org/> Hail Discordia!
++ Ascend Users Mailing List ++
To unsubscribe:	send unsubscribe to ascend-users-request@bungi.com
To get FAQ'd:	<http://www.nealis.net/ascend/faq>