Date: Sun, 20 Dec 92 17:12 PST
From: john@zygot.ati.com (John Higdon)
Newsgroups: comp.dcom.telecom
Subject: Re: GTE and Subscriber Carrier
Reply-To: John Higdon <john@zygot.ati.com>
Organization: Green Hills and Cows
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X-Telecom-Digest: Volume 12, Issue 913, Message 1 of 10

Jack.Decker@f8.n154.z1.fidonet.org (Jack Decker) writes:

> 2) I am told that this system puts six subscribers on one line, and
> there is NO "baseband" subscriber (that is, one of the six does not
> get the actual physical pair ... there's no "A party" and "B party" as
> in some other carrier systems.

It does, however, sound as though it is dysfunctionally the same as the
simple A/B subscriber carrier system that I have oh so much experience
with from GTE.

> 4) The "at rest" idle line voltage is only 15 volts, which has already
> caused some problems with certain equipment I had.  However, the "off
> hook" voltage seems to be a healthy six volts.

The reason for that is simple: the unit is powered off of a very
weenie fifteen VDC supply. Therefore the maximum open-circuit voltage
will be the fifteen that you measured. This can be a problem for any
line-powered equipment or any equipment that detects open-circuit
voltage to determine line status.

> 5) On voice calls, I find it very difficult to hear the person at the
> other end (using a standard 500-type telephone).  However, my modem
> seems to work fine at 2400 bps.  And, wonder of wonders, after being
> told that my fax machine probably would not work on these lines, it
> appears to work fine, at least for outgoing calls (haven't tested it
> on incoming yet, but then I don't receive many faxes).

The biggest problem with all of the subscriber carrier units is
INCONSISTENCY in levels. I had one that was so loud that the
distortion was painful -- that is until the power supply pooped out and
then it just faded away. You might want to check the transmission
times of your fax.  What is probably happening is that there is some
serious speed fallback going on. In other words, you may be able to
send a fax OK, but it may take three times as long as it should.

> 6) Don't know if it's the carrier or the central office, but dial
> pulsing at 20 PPS (pulses per second) is NOT accepted... I had to drop
> back to the standard 10 PPS.  You'd think a digital exchange would
> accept 20 PPS, but maybe not.

This is probably the fault of the subscriber carrier unit being unable
to follow your 20 PPS dialing interruptions. I had one that could not
even transmit 10 PPS; it was so bad that rotary dialing would not work
at all. Fortunately, a touch-tone phone worked fine so I just started
using one.

> 7) If someone drives by using a two-way radio, the signal comes in
> loud and clear on my phone for the few seconds that they are within a
> couple hundred feet of my carrier unit (don't take the distance as
> absolute truth; this has only happened once so the distance estimate
> is a wild guess at best).

These things are very sensitive to RF. Picture, if you will, one of
these things installed at the transmitter site for a high-power FM
station. Then try to imagine what it is like to carry on a
conversation with rock music several times as loud in the telephone as
the party's voice you are trying to hear. Fortunately, I had physical
access to the unit and found that using a garbage can lid
strategically placed, the RF-induced noise could be minimized.

> Should I just leave well enough alone and maybe get a volume control
> handset, or should I keep badgering GTE to give me a better line?

Always badger GTE. That company is going to have to learn someday that
its laughable service does not wash in a non-third-world country. I
now complain about every little thing on every single GTE account that
I am in charge of. If nothing else, it might harm the service stats
enough that the PUC might take notice. This applies to any phone
company; if Pac*Bell gave me anything approaching the miserable
service I have come to expect from GTE, it would be treated the same
way.

> The GTE repairman told me that I am about seven or eight miles out
> from the central office, but you'd think that since I'm on carrier
> anyway, the carrier equipment would boost the signal strength.  Maybe
> not, though.

This whole arrangement is totally obsolete. If you had a real phone
company, you would be served out of a digital remote switch physically
located near you. It, in turn, would be connected via digital circuits
to the master CO located in town. In this way, your telephone service
would sound as though you lived across the street from the central
office.

My business associate lives about twenty miles from his CO and his
phone service and transmission are flawless. But then his telco is
not-yet-GTE-ized Contel, and the switch is not the dreaded GTD-5, but
a DMS-100. Makes a big difference, you know.

> I recall at one time reading some discussion here of a piece of
> equipment designed for "long loops".  I don't recall what it was,
> though, nor whether it would be applicable in this situation.  If such
> a device would be helpful, I wonder what my chances would be of
> convincing GTE to hang one on my line (assuming they've ever even
> heard of such a device, which is doubtful in and of itself).

The only real fix is for your system to be brought into the nineties.
All analog boosters, loop extenders, etc., etc., are bogus when
compared to the now-standard way of doing things. Going digital would
increase capacity by an order of magnitude, make the audio transmission 
perfect, and improve your service in every way. That is why I suspect
GTE has not considered it.


John Higdon  |   P. O. Box 7648   |   +1 408 264 4115     |       FAX:
john@ati.com | San Jose, CA 95150 | 10288 0 700 FOR-A-MOO | +1 408 264 4407