Does 3Com Impact IQ support DOV?

Does 3Com Impact IQ support DOV?

Post by Jerome Mroza » Fri, 01 May 1998 04:00:00



I know that this modem (at about $200 from Computer Discount Warehouse)
has two analog (POTS) ports.  Can I connect my ISDN line to the ISDN
port, and then call my ISP "data over voice" to the ISP analog modem?

Thanks,
Jerome.
--
Jerome Mrozak                     goose  -at-  mcs  -dot-  net
Sun Certified Java Developer & Programmer
Zeal, Inc.                            Sr. Technical Consultant
- "Your Technology Partner" - Northbrook, IL - (847)498-3320 -
http://www.zealinc.com          jeromem -at- zealinc -dot- com

 
 
 

Does 3Com Impact IQ support DOV?

Post by Jerome Mroza » Sat, 02 May 1998 04:00:00




> > I know that this modem (at about $200 from Computer Discount Warehouse)
> > has two analog (POTS) ports.  Can I connect my ISDN line to the ISDN
> > port, and then call my ISP "data over voice" to the ISP analog modem?

> Not really.  You will be sending data over a voice (actually 3.1 Khz
> Bearer), but what folks mean when they say DOV is more precicely when
> one sets the TE (in your case the 3Com TA) to call another TE and
> request
> a 3.1 KHz bearer ( i.e. voice) and use that to send data.  The switches
> in between the TEs can not distinguish this from a voice call and bill
> it as one.

> What you are doing is actually making a standard voice call, albeit one
> that will be used for modulated data.  Now one would think that this is
> some bit better than a POTS call to the other analog device, as the
> analog
> loop is about six feet versus the thousands of feet to your CO.  I have
> some anecdotes that this is indeed the case, and have also read some
> here; especially with the x2 modems.

> I use this with MultiTech Modems and the Alpha Telecom UTA 120 TA; both
> to get any benefit from a (in my case) six inch analog loop, and to save
> a fair bit of money.  At most business rates, *for voice* one ISDN is
> cheaper than two POTS, and the minute rates are the same.

> -sam

My ISP has a reduced rate (same as analog) if I use DOV, and said to
find out if my adapter supported it.  Said I'd connect at 56K both ways,
but if the call is to a normal modem (I'd dial the same number as with
my modem), shouldn't it be limited to V.90 rates?
--
Jerome Mrozak                     goose  -at-  mcs  -dot-  net
Sun Certified Java Developer & Programmer
Zeal, Inc.                            Sr. Technical Consultant
- "Your Technology Partner" - Northbrook, IL - (847)498-3320 -
http://www.zealinc.com          jeromem -at- zealinc -dot- com

 
 
 

Does 3Com Impact IQ support DOV?

Post by Jeffrey Rhode » Sat, 02 May 1998 04:00:00



> My ISP has a reduced rate (same as analog) if I use DOV, and said to
> find out if my adapter supported it.  Said I'd connect at 56K both ways,
> but if the call is to a normal modem (I'd dial the same number as with
> my modem), shouldn't it be limited to V.90 rates?
> --
> Jerome Mrozak                     goose  -at-  mcs  -dot-  net
> Sun Certified Java Developer & Programmer
> Zeal, Inc.                            Sr. Technical Consultant
> - "Your Technology Partner" - Northbrook, IL - (847)498-3320 -
> http://www.zealinc.com          jeromem -at- zealinc -dot- com

That noname formally from Lucent, now GTE BBNplanet, is proud of
reporting that the Portmaster router is able to discern the difference
between an analog modem caller and a 56kbps limited DOV caller. Maybe
this has been upgraded to include V.90 callers, all of which will result
in the ISP receiving a bearer request for *voice* when called. The real
crime is the inability to detect when a 64bkps DOV caller has connected
with a route path in the network supported by clear channels.

Perhaps the V.90 standards will eventually address this problem, so that
ISDN TEs can achiever bi-directional 64kbps between DOV users, in the
event that the underlying network circuits of a *voice* call are
actually able to support clear channels, but the TEs will otherwise
auto-adjust to non-V.90 techniques for DOV 56kbs rate adaption in the
event that the underlying network circuits of an ISDN call are 56kbps
limited for *data*.


 
 
 

Does 3Com Impact IQ support DOV?

Post by Sam C. Nicholson ! » Mon, 04 May 1998 04:00:00



> My ISP has a reduced rate (same as analog) if I use DOV, and said to
> find out if my adapter supported it.  Said I'd connect at 56K both ways,
> but if the call is to a normal modem (I'd dial the same number as with
> my modem), shouldn't it be limited to V.90 rates?
> --

If you call them with a MODEM, you are making a voice call.  (i.e. POTS)
Your call will be answered by a MODEM (how in a second) and the two will
negotiate as best as they can (e.g V.90, x2, Bell 112).

If you call with your ISDN Terminal Adapter, and request an audio
bearer,
then your call will be answered by (most likely) an ISDN PRI connected
device (well, so was the MODEM, but hang on) which will just exchange
bits
with your TA (encoded, but not MOdulated !).

Now the tricky part is how in the heck the NAS (Network Access Server)
knows
how to route your call internally.  One might think that the MODEM call
is
pretty easy.  If it's audio, send it to the MODEM, otherwise just pull
the
bits right out of the data stream.  Cisco does this.  And that means
that
if your TA sets up a call with an audio bearer, a Cisco NAS will send it
to
a MODEM.  For a while, the Ascend boxes used the DNIS (Dialed Number ID)
to
route the call internally.  Then they changed and used the type of call.

Now, I have never know just what incantation to use to set a TA up to
make
a data call but request an audio bearer.  I don't really use TAs for
connecting
to the Inet.  My SunISDN software can be told to "force 56K" to allow
routing
over non-clear channel paths, but doing so doesn't convince BellA that I
made
a voice call.  To me, it's a black art, and I still don't know how it
works
between disparate vendor's equipment, given that they all seem to handle
call routing differently.

Long and short:  If you use a MODEM, you get connex *up to* 56k.
                 If you use an ISDN TA, you get *at least* 56K.

-sam

 
 
 

Does 3Com Impact IQ support DOV?

Post by David Richar » Mon, 04 May 1998 04:00:00





>> My ISP has a reduced rate (same as analog) if I use DOV, and said to
>> find out if my adapter supported it.  Said I'd connect at 56K both ways,
>> but if the call is to a normal modem (I'd dial the same number as with
>> my modem), shouldn't it be limited to V.90 rates?

>Now the tricky part is how in the heck the NAS (Network Access Server)
>knows how to route your call internally.  One might think that the MODEM call
>is pretty easy.  If it's audio, send it to the MODEM, otherwise just pull
>the bits right out of the data stream.  Cisco does this.  And that means
>that if your TA sets up a call with an audio bearer, a Cisco NAS will send it
>to a MODEM.  For a while, the Ascend boxes used the DNIS (Dialed Number ID)
>to route the call internally.  Then they changed and used the type of call.

Livingston (on the PM3 and PM4) has an interesting scheme, I can't find
the documentation, but IIRC, on a voice/speech call the PM allocates a
modem, but also listens to the data coming in for a fraction of a second
after taking the call- if the bits coming down the channel look like data,
it must be a DOSBS call, so the modem is released.

Megazone might be able to explain it fully?

Quote:>Long and short:  If you use a MODEM, you get connex *up to* 56k.
>                 If you use an ISDN TA, you get *at least* 56K.

Good rule of thumb.
 
 
 

Does 3Com Impact IQ support DOV?

Post by Jim Vaugh » Mon, 04 May 1998 04:00:00


ISDN is at least 56K in both directions, the modem is only downstream.

On Sun, 03 May 1998 00:33:49 -0400, "Sam C. Nicholson !!"


>Long and short:  If you use a MODEM, you get connex *up to* 56k.
>                 If you use an ISDN TA, you get *at least* 56K.

Jim Vaughan, Redondo Beach CA
 
 
 

Does 3Com Impact IQ support DOV?

Post by Laurence V. Mar » Mon, 04 May 1998 04:00:00



Quote:>My ISP has a reduced rate (same as analog) if I use DOV, and said to
>find out if my adapter supported it.  Said I'd connect at 56K both ways,
>but if the call is to a normal modem (I'd dial the same number as with
>my modem), shouldn't it be limited to V.90 rates?

Maybe yes, maybe no.  Some products have 'smart' ports that can distinguish
whether the caller is ISDN or modem, not only by the called number, but by
trying both protocols.

Laurence V. Marks
IBM Corp. - Research Triangle Park, NC

 
 
 

Does 3Com Impact IQ support DOV?

Post by Fred R. Goldste » Tue, 05 May 1998 04:00:00



Quote:>Now the tricky part is how in the heck the NAS (Network Access Server)
>knows
>how to route your call internally.  One might think that the MODEM call
>is
>pretty easy.  If it's audio, send it to the MODEM, otherwise just pull
>the
>bits right out of the data stream.  Cisco does this.  And that means
>that
>if your TA sets up a call with an audio bearer, a Cisco NAS will send it
>to
>a MODEM.  For a while, the Ascend boxes used the DNIS (Dialed Number ID)
>to
>route the call internally.  Then they changed and used the type of call.

Ascend didn't change anything.  You get a choice.  IF you assign a telephone
number to the modems, then a call to that number (you can assign several,
actually) goes to the modem.  You can then assign a different number to the
"Ethernet", in which case it's answered as Data, even if the bearer capability
is "audio".  That's how Data Over Voice is done.  Dialed number trumps bearer
capability.  Absent using DNs to discriminate, audio calls all go to the
modems.

I have been told that SOME versions of USR Total Control can be made to do DOV,
but not all, depending on which modem card is used.  I've never seen it work.  
I don't know about Cisco.  Livingston/Lucent, of course, is most clever.

It sounds like Sun's implementation is broken, since it won't let you do DOV.
(In these parts that's taken as profoundly broken!)
--
Fred R. Goldstein   k1io   fgoldstein"at" bbn.com   +1 617 873 3850
Opinions are mine alone; sharing requires permission.

 
 
 

Does 3Com Impact IQ support DOV?

Post by Jeffrey Rhode » Tue, 05 May 1998 04:00:00



> Ascend didn't change anything.  You get a choice.  IF you assign a telephone
> number to the modems, then a call to that number (you can assign several,
> actually) goes to the modem.  You can then assign a different number to the
> "Ethernet", in which case it's answered as Data, even if the bearer capability
> is "audio".  That's how Data Over Voice is done.  Dialed number trumps bearer
> capability.  Absent using DNs to discriminate, audio calls all go to the
> modems.

A Dialed Number trumps ANY bearer capability's incoming request? This
sounds broken to me since there is no way to *sense* whether the caller
is attempting 64kbps. Surely you mean "Dialed number trumps voice bearer
capability and assumes 56kbps data when the number is assigned to
'Ethernet'", right? Can an Ascend be configured for incoming 64kbps CSD
data callers only, in order to refuse 56kbps CSD and all voice callers,
so that a given dialin number can be reserved for *premium* 64kbps
callers? Maybe not, so I say the Ascend is broken, because it won't
support 64kbps DOV and 64kbps-only CSD dialin numbers. I would consider
it to be broken, too, if CSD callers dialing the Dialed Numbers assigned
to Ascend analog modems get answered by modems, or does the bearer
capability request trump Dialed Number in this case?

Quote:

> I have been told that SOME versions of USR Total Control can be made to do DOV,
> but not all, depending on which modem card is used.  I've never seen it work.
> I don't know about Cisco.  Livingston/Lucent, of course, is most clever.

Can't do 64kbps DOV. Wonder if anyone can do 64kbps-only CSD?

Quote:> It sounds like Sun's implementation is broken, since it won't let you do DOV.
> (In these parts that's taken as profoundly broken!)
> --

I guess you must be the judge and jury as to what is broken with respect
to US ISDN DOV? Why you consider 56kbps DOV to be mandatory and 64kbps
DOV to be misguided is beyond me.

regards, jcr

 
 
 

Does 3Com Impact IQ support DOV?

Post by MegaZo » Thu, 07 May 1998 04:00:00



Quote:>Livingston (on the PM3 and PM4) has an interesting scheme, I can't find
>the documentation, but IIRC, on a voice/speech call the PM allocates a
>modem, but also listens to the data coming in for a fraction of a second
>after taking the call- if the bits coming down the channel look like data,
>it must be a DOSBS call, so the modem is released.

The PM3 (and PM4) is built around a data switch architecture.  When a
call is received over PRI with a VOICE flag, or any call over CT1 is
received, the data stream is simultaneously assigned to a DSP and to
the HDLC controller.  HDLC will always sync up practically immediately
if it is indeed a DOSBS call.  If this happens the PM-3 will then release
the DSP back into the pool.  If the HDLC fails, the HDLC controller
releases the stream and the DSP continues to try as a modem.

This allos the unit to take 56K and 64K ISDN DATA, 56K ISDN DOSBS, and
modem calls on one phone number on a PRI, and 56K ISDN DOSBS and modem
calls over one number on a CT1.

-MZ
--

"A little nonsense now and then, is relished by the wisest men" 781-788-0130

 
 
 

Does 3Com Impact IQ support DOV?

Post by MegaZo » Thu, 07 May 1998 04:00:00



Quote:>Can't do 64kbps DOV. Wonder if anyone can do 64kbps-only CSD?

Nope, it can't.  I'm not aware of any ISDN server that does 64K DOSBS.
Know what?  No one else seems to care.  I have *never* understood why
this is such an issue for you, you bring it up constantly.  But no one
ever requests it as a new feature, the rest of the world doesn't appear
to care at all.

As for forcing 64K DATA only, not that I know of.  You can use RADIUS to
deny any connections that aren't 64000 - as long as the NAS sends
Connect-Info and RADIUS supports something like the Lucent Connect-Rate
check item.  Connect-Rate = 64000  Anything lower than 64000 will be denied.
And with the current 3.8 betas PortMaster-3s can use 'call check' to contact
RADIUS *before* answering the call.  So I suppose you can use this system
to accept only 64K DATA calls.  (Since they don't do 64K DOSBS that is
the only call type left at that speed.)

-MZ
--

"A little nonsense now and then, is relished by the wisest men" 781-788-0130

 
 
 

Does 3Com Impact IQ support DOV?

Post by Jeffrey Rhode » Fri, 08 May 1998 04:00:00




> >Can't do 64kbps DOV. Wonder if anyone can do 64kbps-only CSD?

> Nope, it can't.  I'm not aware of any ISDN server that does 64K DOSBS.
> Know what?  No one else seems to care.  I have *never* understood why
> this is such an issue for you, you bring it up constantly.  But no one
> ever requests it as a new feature, the rest of the world doesn't appear
> to care at all.

Yeah, right.

Everyone who uses 56K DOSBS/DOVBS doesn't want an extra 8K bandwidth
when the underlying circuits of their call can support it. What planet
are you from?

Maybe you were under a different assumed name back in 1993 or just don't
remember when I defined the concept, right here in cdi, of probing a
circuit switched connection for various data rates starting at 64K, then
56K, then 48K, etc. Sort of like what X2/56KFlex/V.90 does with other
chunks, I might add. If I remember correctly, I probably had the
foresight to claim a copyright.

With all the muddled routing that is possible in the US, 64kbps data is
an elusive capability for many carriers. Not for AT&T, 64kbps may cost
more, but it at least when you ask for it, to many even *
locations, then you will get it answered as 64kbps if possible. Some
applications require 64kbps, especially backup systems for frame relay
that need as much bandwidth as possible and fast, so a billing
relationship with AT&T Accunet (1-800-943-8288) with casual dialing
102881 prefix can make that possible without having to change long
distance companies.

I remember sometime back in 1986 or 1987 when I brought the concept of
DOSBS/DOVBS to my employer, who was then what is now Lucent. I was told
it was illegal, that no company would touch the product. So I've been
told that the rest of the world doesn't care before and seen that
change.

I can only speculate that the reason no US manufacturer of ISDN
equipment (except maybe Digi) supports bi-directional 64kbps is that
they are intimidated by the original copyright notices I made back in
1993 and 1994 ;-)


1998

 
 
 

1. 3com Impact IQ External and 112k DOV?

I have a 3COM Impact IQ External TA and was wondering if it could do 112k
DOV?

I live in Boston, MA.

I have upgraded to firmware 3.11.

I have also emailed 3COM support.  Be interesting to see what they also
have to say and how long it takes them to respond.

Thanks much in advance.

--
-------------------------

Scott Ehrlich Consulting                http://www.shore.net/~sehrlich  
Amateur Radio Callsign: wy1z

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