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From: eds@solar.UUCP (E.SCHULZ)
Newsgroups: net.dcom
Subject: Re: DSU/CSU recommendations?
Message-ID: <371@solar.UUCP>
Date: Fri, 21-Jun-85 21:47:03 EDT
Article-I.D.: solar.371
Posted: Fri Jun 21 21:47:03 1985
Date-Received: Sun, 23-Jun-85 04:22:23 EDT
Organization: AT&T Information Systems, Holmdel NJ
Lines: 57

This is a repeat of the mail I sent to Phil Ngai about AT&T's new
DSU/CSU products for DDS.  I'm posting it at his suggestion that
it's of public interest (I hope it is!).
--------------------
I work in the AT&T-IS department that develops DSU/CSUs, so this is
definitely a plug, not an unbiased opinion!

In September 1984, we introduced the 2500-series DSU/CSU for DDS.
The subrate (RS-232) set sells for $850, and the 56Kb/s (V.35) is
$950, quantity 1.  We do have a competitive quantity discount
schedule.

Here are some of the features of the 2500:
	- LCD graphic display that shows EIA leads, network status
	(no signal, out of service code, streaming terminal),
	loopbacks, test conditions, test results, operating speed.
	- Pushbutton switches for digital loopback, local loopback,
	remote loopback (point-to-point only), internal test pattern
	generate and compare, and LCD test.  These switches can be
	disabled by a strap, if you're afraid of bumping into them.
	- Lots of options (i.e. standard but optionable): elastic
	store to support off-net analog private line extensions;
	streaming terminal detection and disable (for multipoints);
	circuit assurance (like a 500B); system status (like 500B);
	DDS, internal, external, and slave LDM timing so that the
	2500 can be used as a limited-distance modem; continuous or
	switched request-to-send.
	- Stand-alone or multiple-mounted units.  Multiple mounting
	has a single front panel that is shared among 8 DSUs in the
	shelf.
	- For LADS applications, the set will work reliably over a
	range of speeds, cable lengths, and gauges: 2.4Kb/s, 19 AWG,
	20.0 miles; 56Kb/s, 26 AWG, 2.7 miles; and lots in between.
	- The CSU functions are done in two HICs, and all the digital
	functions are done in a single LSI chip, so our set's
	reliability should compare favorably with our competitors'.
	The box runs really cool, too.

I don't know what to say about DDS being lousy in Texas.  If it's
real DDS, there are definite error-free seconds and availability
specs that AT&T-C and the BOCs should be cooperating to provide.  If
that's not the case, you have a right to complain.  Our sets should
help you to find where the trouble is, if there is trouble.

On June 24, we are announcing the 2600-series DSU/CSU that I worked
on.  This is fully compatible with the 2500 (same circuitry), with
stuff added to allow connectivity to our Dataphone II Diagnostic
Control Devices and multipoint addressability for testing, if that
turns you on.

If you have any questions about our stuff, or even about any of our
competitors' products, please drop me a line or call me.  Here in
the development lab, we don't get to talk to enough real customers.

	Ed Schulz
	{ihnp4 or anything else in AT&T}!solar!eds
	201-834-3838