[comp.dcom.telecom] Test Lines

macy@cwjcc.ins.cwru.edu (01/08/90)

[Moderator's Note: This was mailed to the Digest on December 25. It
arrived January 5!! The dating above was changed so it will have a couple
days life in Usenet.   PT]

In article <2352@accuvax.nwu.edu> John Higdon <john@bovine.ati.com> writes:
>X-Telecom-Digest: Volume 9, Issue 587, message 6 of 9

>> I noticed a couple of years ago in PacBell land in Northern CA that
>> the 0020 suffix in just about any prefix always went to a loud,
>> continuous tone, which has about a 1/2 sec gap every 15 secs or so.

>This tone is known in the biz as the "miliwatt". It is a 1004 hz tone
>that originates with a power of .001 watt in the CO. It is a standard
>so that by dialing that number, a field tech can readily measure the
>loss on that particular circuit.

There are several other "standard" test lines that are commonly used.
Working from memory here are a few...( it's been a few years...)

	1004 Hz milliwatt tone (commonly known as 0.0 db tone)
	Quiet line, terminated
	Quiet line, unterminated
	Quiet line, synchronous
	1004 Hz low level, -20 db I think
	Sweep tone, for frequency response test
	Various progress tones (busy, intercept, etc) for equip. test
	Responder lines (send them 1004 Hz. 0.0 db and they respond)
	Dial test lines (pulse and DTMF), respond with beeps is dial is OK
	ANI line
	Ringback line  (these have been talked to death here)
	Automatic analysis line (call it, hang up, the line you called from
          is checked and you are called back with "reading" info)  GTE's
          Fourtel has an option like this, too.

Of the above, 1004 and terminated quiet line are the most freqently used.

>There was a number that a phone man used once on some PBX trunks that
>I had installed that produced the strangest sounds I had ever heard.

This was probably a "sweep" line, which uses a set of tones to check
the frequency response and phase envelope delay characteristics of a
line, usually a special test unit is used at the site.  These were
often used to setup and test "conditioned" lines and "program" lines.
They do sound very odd when you listen to them.

These lines often are set up to require a test set to interact with
the CO unit, or they won't respond. Calling one with a 2500 set
usually gets a simple beep, then they hang up.

And then there is automated testing...

GTE has several "access" lines here to use the automation, but few of
the craftsmen use them.  Their common gripe is the Fourtel is "too
sensitive" and responds to many type of equipment as "trouble".  At
one time, GTE dispatched a repairman on every Fourtel ticket...and
they found alarms, data sets, fax machines, key sysetms, PBX's and
even a few single line phones created tickets...

So now the GTE people run them in a more traditional format...each
Fourtel ticket is checked by a human on the test board first before it
is dispatched.  Now they use Fourtel to spot "trends" on groups of
lines (like spotting wet cable) primarily, and individual lines are
checked individually.  A GTE foreman told me that a recent upgrade to
the system had solved a lot of these problems.

Automated line testing still tends to set off a lot of alarms with
"telephone line cut monitors", especially if it's a long loop.  We've
had to tell GTE to "bypass" several of our customers (it's actually a
class mark in the CO database).  Ohio Bell line test stuff has caused
us few problems.

Craftsmen are still resisting the use of automated test and respond
lines, though.  They still want to talk to a testboard operator.
(Gives them time to drink their coffee, while they wait on hold...)

I always used to get mad at holding, and have the frame open the pair,
and then use my trusty old Simpson 260 along with some 22 volt
batteries to clear the pairs....

I'd be very interested in hearing anyone else's info, experiences, and
problems with test lines and/or automated testing.


 Macy M. Hallock, Jr.     macy@NCoast.ORG         uunet!aablue!fmsystm!macy
 F M Systems, Inc.      {uunet!backbone}!cwjcc.cwru.edu!ncoast!fmsystm!macy
 150 Highland Drive      Voice: +1 216 723-3000 Ext 251  Fax: +1 216 723-3223
 Medina, Ohio 44256 USA   Cleveland:273-3000 Akron:239-4994 (Dial 251 at tone)
 (Insert favorite disclaimer here)   (What if I gave a .sig and nobody cared?)