> 9600 bps over conditioned leased lines?

[Steve Dyer]

I am looking for modems which can support rates higher than 9600 baud
over 4-wire full-duplex D1-conditioned analog leased lines, aka 3002
circuits. I'm designing a small wide-area network and 9600 baud really
won't cut it for the backbone, but 56kb digital service is just too
expensive and not cost-effective. Anyone know of modems which can
support 19.2kb or higher synchronous rates over fairly long runs
(10-50 miles)?
--
---
Steve Dyer
spdcc!dyer
dy...@harvard.harvard.edu

[Phil Ngai]

In article <2...@halleys.UUCP> dy...@halleys.UUCP (Steve Dyer) writes:
>I am looking for modems which can support rates higher than 9600 baud
>over 4-wire full-duplex D1-conditioned analog leased lines, aka 3002
>circuits. I'm designing a small wide-area network and 9600 baud really
>won't cut it for the backbone, but 56kb digital service is just too
>expensive and not cost-effective. Anyone know of modems which can
>support 19.2kb or higher synchronous rates over fairly long runs
>(10-50 miles)?

There's this little company in Massachusetts named Codex which makes
a product which will do what you want. It is called the 2680 trellis
coded 19200 bps modem. It's about $30,000 for a pair.

Still think DDS is expensive?
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<phil <ngai +1 408 749 5720
<u<uC<p: <[ucbvax,decwrl,ihnp4,allegra<]!amdcad!phil
AR<pA<; amdcad!ph...@decwrl.dec.com

[Pria Graves]

In article <13...@amdcad.UUCP> ph...@amdcad.UUCP (Phil Ngai) writes:

> In article <2...@halleys.UUCP> dy...@halleys.UUCP (Steve Dyer) writes:
> >I am looking for modems which can support rates higher than 9600 baud
> >over 4-wire full-duplex D1-conditioned analog leased lines, aka 3002
> >circuits.
>

> There's this little company in Massachusetts named Codex which makes

Not so little..... they are part of Motorola
--
Pria ...!{ihnp4,hplabs,amd,nsc}!amdahl!pag00
(408) 746 7539

(Disclaimer: even I don't necessarily agree!)

[Steve Dyer]

>There's this little company in Massachusetts named Codex which makes
>a product which will do what you want. It is called the 2680 trellis
>coded 19200 bps modem. It's about $30,000 for a pair.
>
>Still think DDS is expensive?

Right now, I'm finding that 56kb digital service, at least between the points
that I'd be interested in, is more than 7X as expensive as analog 9.6kb lines,
and the necessity to keep recurring costs low is a major factor in the design.
While I'll agree that $30K is a bit steep, I've already received pointers to
other modems in the 14.4/16/19.2kb range for a lot less, which information I'll
summarize once I sift through it all.
--
Steve Dyer
dy...@harvard.HARVARD.EDU
{linus,wanginst,bbnccv,harvard,ima,ihnp4}!spdcc!dyer

[Phil Ngai]

In article <40...@amdahl.UUCP> pa...@amdahl.UUCP (Pria Graves) writes:
>In article <13...@amdcad.UUCP> ph...@amdcad.UUCP (Phil Ngai) writes:
>> There's this little company in Massachusetts named Codex which makes
>
>Not so little..... they are part of Motorola

I was being sarcastic, obviously a mistake on my part.

[Scott Brim]

Have you considered duoplexers? (two 9.6 lines in tandem to create a
logical 19.2 connection)

[Mark Horton]

I haven't followed it closely, but yesterday a salesperson pointed
at a TeleByte modem, said the cost was $3500 each, and that it did
19.2K over regular dialup lines. Part of this is probably done with
data compression, so it may not help your application.

Also, if you're willing to wait a while, you might be able to use
ISDN. That will give you 2 64K switchable circuits over 4 wires.
In the US I think you have to be on a 5ESS, but I hear our local
5E is scheduled to have ISDN available in 1987 sometime.

Mark