[sci.electronics] Looking for twisted-pair simulator

elmquist@nachos.SSESCO.com (Chris Elmquist) (12/06/90)

I'm looking for a piece of test gear that can be used to simulate
long lengths of twisted-pair wiring...  loss and distortion are
the important things to simulate..  noise and cross-talk are not.

Ideally, this device would simulate variable lengths of line with
some kind of tap arrangement perhaps.  We are trying to get away
from buying miles of TWP and stringing it around the lab.

Any clues would be appreciated.

Thanks.

Chris
-- 
Chris Elmquist, N0JCF
Internet: elmquist@SSESCO.com
   AMPRN: N0JCF@WB0GDB.MN.USA.NA
 BellNet: (612) 785-3516

larry@kitty.UUCP (Larry Lippman) (12/07/90)

In article <273@nachos.SSESCO.com>, elmquist@nachos.SSESCO.com (Chris Elmquist) writes:
> I'm looking for a piece of test gear that can be used to simulate
> long lengths of twisted-pair wiring...  loss and distortion are
> the important things to simulate..  noise and cross-talk are not.
> 
> Ideally, this device would simulate variable lengths of line with
> some kind of tap arrangement perhaps.  We are trying to get away
> from buying miles of TWP and stringing it around the lab.

	I have two Allen-Tel GB-8970 artificial line test boxes that will
do exactly what you want.  Each box will simulate over 100 kft of cable in
different gauges.  I purchased these from Graybar Electric in 1971 for an
absurd amount of money.

	I don't know if Allen-Tel still manufactures such a product,
however.  I would suggest that you contact a local Graybar distributor.
I believe that Wilcom and Porta-Systems also manufacture artificial
line boxes.

	There are also active simulators which create phase jitter and
various types of distortion, but they do not simulate the distributed
network characteristics of long loops.

Larry Lippman @ Recognition Research Corp.  "Have you hugged your cat today?"
VOICE: 716/688-1231   {boulder, rutgers, watmath}!ub!kitty!larry
FAX:   716/741-9635                  {utzoo, uunet}!/      \aerion!larry

lstowell@pyrnova.pyramid.com (Lon Stowell) (12/08/90)

Depends on the frequencies of the twisted pair you want...

If you are looking to duplicate the public telco dial or leased
line, there are a couple boxes...they can even emulate the CO
switching...

The most commonly used one is the TAS 1010...it can duplicate
virtually ANY impairment that a telco circuit can...

For LAN frequencies, good luck.