SUMMARY: Utilizing 56K digital line

From: Leon Howorth (leonh%hhb@Princeton.EDU)
Date: Fri Apr 03 1992 - 01:21:10 CST

SUMMARY: Utilizing 56K digital line

My original posting (somewhat compressed):
Can one use a 56K digital line in such a way that connection and
susequent data transmissions are accomplished automatically?

Is there a way to use the line for UUCP data transmission on an "as-needed"
basis only? (Such as accomplished via modems in the current environment).
If I cannot use UUCP, is there some other mechanism for using the line
for data transmission between the two sites on an "as-needed" basis
WITHOUT manual intervention?
For example, I am somewhat familiar with types of DSU's available, and
have used a Dial-up (Switched Digital) version DSU before. But this
requires manual intervention to establish the connection when needed.

***I should have specified that this would be a "switched 56K" channel.***

Anyway, thanks to the following for replies, which helped to point
me in certain directions for my subsequent research:

Bob Sutterfield <MorningStar.Com!bob>
spdev.East.Sun.COM!tgsmith (Timothy G. Smith - Special Projects)
Mike Raffety <!miker>!mdl (J. Matt Landrum)

Although I do not have the "best" solution for our particular needs as yet,
I would like to pass along some information I have obtained with regard to
types of DSU's that could be used in this situation. I'll put them into
4 catagories:

1. The type which requires manually dialing a number or pressing a button
to have it dial a pre-stored number. An example is an AT&T Paradyne 2600,
one of which I already have and use for bulk file transfers to/from
another site about once per day. Since this requires manual intervention,
it is NOT what I am looking for.

2. I found a number of DSU's which contain RS-366 (dial protocol) ports
for both initiating dialing and passing dialing information to the
unit. I don't think that finding something to attach to the DSU and
make use of that protocol would be too easy though.

3. Another feature included in some DSU's is automatic single number
dialing initiated by raising DTR at either the V.35 or RS-232 interfaces
(and many have both V.35 and RS-232 available). This is limited to only
one choice of a pre-stored number though.

4. Finally, some DSU's provide an RS-232 port which can be used
to dial from a computer or terminal using AT commands. This is

Some examples of DSU's that I found with most or all of the above
features are:
ADC Kentrox Switched 56 DSU Model 200
Dowty DCP3058 Switched 56 Terminal Interface Unit
Integrated Network Corp. 1056 DSU

[NOTE: I include the above as examples **ONLY** I am not endorsing anything].

I also understand that the type of capability I'm looking for is or will
soon be available on various internetworking routers.

Now I need to decide what I would like to have attach to one of these DSU's
(i.e., computer with specific high-speed interface, some type of
internetwork router attached to my LAN, etc.). I'll post again when we
successfully test something we like.

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