TELECOM Digest Mon, 21 Feb 94 10:07:00 CST Volume 14 : Issue 95

TELECOM Digest Mon, 21 Feb 94 10:07:00 CST Volume 14 : Issue 95

Inside This Issue: Editor: Patrick A. Townson

Re: How to Share a 64Kbps Leased Line With Ten Users (Tohru Asami)
Re: How to Share a 64Kbps Leased Line With Ten Users (Al Varney)
Re: How to Share a 64Kbps Leased Line With Ten Users (Barton F. Bruce)
Re: Experience With Cable & Wireless (Good or Bad) (Hamish Moffatt)
Re: Experience With Cable & Wireless (Good or Bad) (Dave Levenson)
Re: Cell Phone Welcome Message (Tom Wiencko)
Re: Help Needed Building Voice Mail Indicator Light (William C. DenBesten)
Re: How to Build Modified Three-Way Calling? (Dave Held)
Re: How to Expand the Range of Cordless? (Dave Held)
Re: 900 Mhz Phone Power Output (Paul Cook)
Re: 900 Mhz Phone Power Output - Correction (Alex Cena)
Re: Need Information About Telemate (Sean P. Peacock)
Re: VCR and Touch-Tones (Stefan Bethke)

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From: [email protected] (Tohru Asami)
Subject: Re: How to Share a 64Kbps Leased Line With Ten Users (9600 Baud)
Organization: KDD R.&D. Labs.
Date: Mon, 21 Feb 1994 03:29:25 GMT

Thanks for many replies on my previous question. Here I summarize
the responses which I received via E-mail.

>> I've heard that Pacific Communication Science Incorporated (PCSI) is
>> selling a data compression machine, called CS-8000, which can compress
>> a 64Kbps data link into a 9600bps data link.

>> I wonder if the following communication is possible for cost saving.

>> +---+ +---+
>> | M | | M |
>> 64Kbps 9600bps | U | | U |9600bps 64Kbps
>>User------[CS-8000]--------+ L | | L +------[CS-8000]------User
>>User------[CS-8000]--------+ T | | T +------[CS-8000]------User
>>User------[CS-8000]--------+ I | 64Kbps| I +------[CS-8000]------User
>>User------[CS-8000]--------+ P +-------+ P +------[CS-8000]------User
>>User------[CS-8000]--------+ L | leased| L +------[CS-8000]------User
>>User------[CS-8000]--------+ E | line | E +------[CS-8000]------User
>>User------[CS-8000]--------+ X | | X +
>> | O | | O |
>> | R | | R |
>> +---+ +---+

>> My questions are as follows:
>> 1. Are there any multiplexors from 9600bps to 64Kbps?
>> 2. Are they compatible with CS-8000?
>> 3. How much are they?
>> 4. What companies are selling them?
>> 5. What kind of problems do we enconter in the above configurations?
>> 6. Did anyone try the same communication method?

David G Lewis(AT&T Bell Laboratories, [email protected]) writes:

I don't know anything about te CS-8000, but the capability to mux up to 8
9.6kb/s lines on a single 64kb/s line is known as SRDM, or SubRate Data
Multiplexing. It's been a capability of the DDS (Digital Data System,
formerly Dataphone(R) Digital Service) service for quite some time.

A company that deals with DDS CSU/DSUs (Channel Service Unit/Data Service
Units) would be the first place I'd look for info on SRDMs.

Elya S. Kurktchi([email protected]) writes:

However, do you really want to break up a 64kbps line into 10
9600bps lines? Why not use a repeater which has 8-24 ports.
Something like this:
+---+ +---+
| | | |
64Kbps 64kbps | | | |64kbps 64Kbps
User------[CS-8000]--------+ | | +------[CS-8000]------User
User------[CS-8000]--------+ R | | R +------[CS-8000]------User
User------[CS-8000]--------+ E | 64Kbps| E +------[CS-8000]------User
User------[CS-8000]--------+ P +-------+ P +------[CS-8000]------User
User------[CS-8000]--------+ E | leased| E +------[CS-8000]------User
User------[CS-8000]--------+ A | line | A +------[CS-8000]------User
User------[CS-8000]--------+ T | | T +
| O | | O |
| R | | R |
+---+ +---+

A repeater boosts that original 64kbps signal and then repeats it
as far away as you want it. Your users can then have 64kbps lines.
But, if you only want them to use 9600bps, then configure their
computers to only send the data at 9600bps, while still retaining
those 64kbps lines.

How does that sound?

Oh yeah, by the way. A repeater is only $459 US dollars. That I believe
is cheaper than the CS-8000 you were talking about. You can also get
a terminal server (Xyplex for instance) and configure each port at 9600bps
and then just run slip to their computer or ppp.

Thanks for your help.

Tru

Manager of Network Engineering Support Group, KDD R&D Labs.
2-1-15 Ohara Kamifukuoka-shi, Saitama 356, Japan
Phone: +81 492 66 7890, FAX : +81 492 66 7510
KDD = an international telecommunication company in Japan

------------------------------

Date: Mon, 21 Feb 94 09:12:01 CST
From: [email protected]
Subject: Re: How to Share a 64Kbps Leased Line With Ten Users (9600
Organization: AT&T

In article <[email protected]> [email protected]
(Tohru Asami) writes:

> I've heard that Pacific Communication Science Incorporated (PCSI) is
> selling a data compression machine, called CS-8000, which can compress
> a 64Kbps data link into a 9600bps data link.

[diagram of requested 9600bps-to-64Kbps multiplexer removed]

> In this case, a User uses a telephone or FAX, and he may not intensively
> use his 64Kbps line.

First you talk about a compressing 64Kbps "data links", and now you
are talking about "voice" and FAX.

While "he" may not intensively use his line, the diagram you show
has multiple fixed 9600bps signals multiplexed to 64Kbps at all times.
Thus an idle line consumes as much bandwidth as an "in use" line. (Or
at least an idle CS-800 consumes as much bandwidth as a busy one.)

You are unlikely to get FAX to work over such an arrangement (the
9600bps interface is a bottleneck). For voice, echo handling (for
longer distance calls) may be a problem.

But why not ask PCSI about how folks use their machine?

Al Varney

------------------------------

From: [email protected]
Subject: Re: How to Share a 64Kbps Leased Line With Ten Users (9600
Organization: Digital Equipment Computer Users Society
Date: 20 Feb 94 19:15:05 -0500
Organization: Cambridge Computer Associates, Inc.
In article <[email protected]>, [email protected]
(Tohru Asami) writes:

> I've heard that Pacific Communication Science Incorporated (PCSI) is
> selling a data compression machine, called CS-8000, which can compress
> a 64Kbps data link into a 9600bps data link.

> I wonder if the following communication is possible for cost saving.

> +---+ +---+
> | M | | M |
> 64Kbps 9600bps | U | | U |9600bps 64Kbps
> User------[CS-8000]--------+ L | | L +------[CS-8000]------User
> User------[CS-8000]--------+ T | | T +------[CS-8000]------User

The PCSI type box (and there are several other brands, but PCSI does a
GOOD job of returning your idle bandwidth to something else when folks
go on hook) should only be used for adding compressed voice to an
available data link, IMHO.

Terminal sessions and about everything else should all on ethernet at
both ends and bridged or routed between sites via ONE SYNC port that
gets all the residual bandwidth and that has its SYNC clock rate
changed as more or less bandwidth is available.

Yes, some of these types of boxes do do statmuxing and tdm and
terminal server to ethernet and even ethernet bridging integral. My
opinion is that in general you want to NOT do all that in this box.
Statmuxing async traffic is slightly old fashioned since the advent of
terminal servers on ethernet. The integral ethernet bridging is hardly
as spiffy as using a powerful but innexpensive external one such as a
Gandalf 5220. The SYNC TDM functionality might be useful, but why
isn't EVERYTHING on your ethernet?

This class of box **DOES** excell at packing voice traffic into a
small bandwidth channel. At too low a speed you get the 'drunk-Spanish-
Donald-Duck' effect, but at higher speeds the speech is quite good.
They also will recognise FAX traffic and the DSP chip can just as
easily demodulate it as it can digitise and compress voice, so the
pass FAX traffic as data bits NOT as compressed FAX tones, and then
remodulate it at the far end. NB that if you have the channel at 5.6kb
or 8.0kb, your FAX will NOT go at 9.6 or 14.4, but will be negotiated
down to probably 4.8kb, BUT will work.

If you have eight remote phone users that may not all be off hook at
once, use these voice channels as E+M tie trunks between PBXes and use
LESS than eight voice channels -- this will save BIG $s. Try running
at 5.6kb and get ALL the available unused bandwidth when folks are on
hook auto-allocated to the SINGLE SYNC line between sites that has an
ethernet bridge or router on it and all terminal or other traffic then
passes that way. The PSCI box only takes about 1.8kb overhead, so with
everyone on-hook, you can get a tad better than 62kb for your
bridge/router. Be sure your configuration leaves enough to reliably
run the bridge/router when ALL voice channels are in use.

Be sure your bridge/bouter can tolerate a changing clock. Most can, as
this is a VERY common and popular application, but ...

------------------------------

Subject: Re: Experience With Cable & Wireless (Good or Bad)
From: [email protected] (Hamish Moffatt)
Date: Sun, 20 Feb 1994 19:36:07 +1100
Organization: Cloud Nine BBS, Melbourne, Australia.

In TELECOM Digest, [email protected] writes:

> Does anyone have any experience with Cable & Wireless? They are bidding on
> both our voice and data service, and any information, good or bad, would be
> appreciated. You can reply via email, and I'll post a followup.

Cable and Wireless run the Mercury phone service in the UK. They are
also one of the the major partners in Australia's second long distance
company, Optus Communications. (Optus and Mercury are similar services
for Australian and England, respectively).

Optus are doing a fine job down here. You should be okay ...

Hamish Moffatt, [email protected]
System Administrator Fax: +61 (0)3 803 6954
Cloud Nine BBS, Melbourne. Voice: +61 (0)3 803 1326
+61 (0)3 803 6954 (v.32bis) 3:635/552@fidonet

------------------------------

From: [email protected] (Dave Levenson)
Subject: Re: Experience With Cable & Wireless (Good or Bad)
Organization: Westmark, Inc.
Date: Sun, 20 Feb 1994 15:17:08 GMT

We have used Cable & Wireless 800 service for several years. They
are the only (or perhaps, at this point, the first) inter-exchange
carrier to deliver calling number (probably ANI, maybe CID) to us in
real time using the NJ Bell Caller*ID service.

C&W is the default (dial-1) carrier at my residence. No complaints
with their outbound service, either.

Dave Levenson Internet: [email protected]
Westmark, Inc. UUCP: {uunet | rutgers | att}!westmark!dave
Stirling, NJ, USA Voice: 908 647 0900 Fax: 908 647 6857

------------------------------

From: [email protected] (Tom Wiencko)
Subject: Re: Cell Phone Welcome Message
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Mon, 21 Feb 1994 00:04:33 GMT

[email protected] (Gary huntress) writes:

> My in-laws have a new Motorola flip phone that they love very much.
> They recently took a trip to Florida and while driving on Rt. 95 the
> phone rang and they got some sort of a "welcome" message from one of
> the local service providers. My FIL is constantly amazed by all the
> technology at work here and he would like to know basically how this
> works.

> I assumed that the phone, while in standby, can detect when it enters
> and leaves each cell. And when it sees that it enters the cell of a
> new carrier it (the phone) transmits some sort of a "here I am"
> message obviously this includes his phone number or some sort of
> serial number so that the cell can call back with the "welcome" msg.

> Is this about right?

Yep, just about. When a cellular phone notices that it is talking to
a cell site that is not connected to its home switch (or system) it
broadcasts a thing called Autonomous Registration. This information
can be picked up by the network equipment which can then cause an
automated calling system to place a "welcome call." The subscriber is
not charged for this call.

This same functionality can be used to assist in fraud detection,
since the visited system can then query the subscriber's home system
and find out if the mobile phone is a valid subscriber.

Pretty fancy, these cellular phone systems.

Tom Wiencko [email protected]

[TELECOM Digest Editor's Note: Pretty expensive, too. PAT]

------------------------------

From: [email protected] (William C. DenBesten)
Subject: Re: Help Needed Building Voice Mail Indicator Light
Organization: Bowling Green State University
Date: Sun, 20 Feb 1994 23:36:31 GMT

In article <[email protected]>, [email protected] (Marc A.
Sarrel) wrote:

> Does anyone have plans to build a small (less than a few cm^3) circuit
> that would detect the presence of messages and flash an LED or
> something?

> Alternatively, I have a SPARCstation LX (Solaris 2.3) sitting on my
> desk with a couple of unused ISDN ports. Is there some software that
> would allow me to run my phone line through those ports and give me an
> indication on my screen when I have messages (sort of like xbiff)?

> We're soon to get Pacific Bell voice mail in our section at work. The
> voice mail is already installed where I work, but it is not
> universally used.

> Anyway, the way the system is set up, we have to lift the handset and
> listen for the beeps to tell if we have messages. We have to pay
> extra to get a phone with an indicator light or even more for a phone
> with an LCD type display. That's not going to happen.

> I'm not a EE, but I can probably build the thing if it's not too
> complex ...

Note: these things are possibly local to your telephone switch. What I
know has been determined by paying attention to our local PBX.

The light works by noticing a voltage on the line (I would guess 50
volts or so) that is quite a bit below ringing voltage(~200v), but
above battery (24v). I suspect that the light is connected with a few
zener diodes to prevent its lighting unless the voltage is in range.

The big problem for you is that the switch can be programmed not to
send this code out. We did had a line that was mis-programmed and
would tap its ringer whenever it had a message. Since I had the
office next door, I had this problem taken care of. The stutter
dialtone is a separate system, and can be enabled when the lamp is
not.

Put a volt meter on your phone line and send yourself voice mail to
see just what is going on. Of course, I would not dream of doing this
sort of thing with our phone switch, without permission from our
telecommunciations department :-). You could also borrow a phone with
a lamp to see what happens on your line.

William C DenBesten is [email protected] or bgsuopie.bitnet

------------------------------

From: [email protected]
Subject: Re: How to Build Modified Three-Way Calling?
Date: Mon, 21 Feb 94 02:32:28 -0500
Organization: Delphi ([email protected] email, 800-695-4005 voice)

Misuzu Nakazawa <[email protected]> writes:

> I am trying to build a three-way telephone conference circuit where
> parties A and B can communicate with party C (in both directions). C
> can hear A and B and A and B can hear C. The catch though is that I do
> not want A and B to be able to hear each other at any time during the
> call.

Although not impossible (given digital signal processing) it is nearly
so if you are using "ordinary" two-wire analog voice lines. The problem
is that there is always some "echo" in the hybrid (the circuit that
permits you to send two-way voice over only two wires). This echo will
permit A and B to hear each other anytime C can hear them and they can
hear C.

If you REALLY need to do this, buy two telephones with headsets and wear
both headsets at the same time. As long as there is no leakage between
your ears and your mouth, A and B will not hear each other.

Dave

------------------------------

From: [email protected]
Subject: Re: How to Expand the Range of Cordless?
Date: Mon, 21 Feb 94 02:53:56 -0500
Organization: Delphi ([email protected] email, 800-695-4005 voice)

<[email protected]> writes:

> Can anyone tell me how far the power can be boosted for a cordless
> phone system, if it is modified at its best?

It is usually impractical to modify the power of a commercially
designed transmitter. The designer has usually selected components
which are properly sized for the target power output. If a simple
adjustment could increase the power, the designer probably failed to
produce the lowest cost design for the intended power level.

A further complication is that a cordless phone has both a transmitter
and receiver which both operate at the same time, a non-trivial
achievement which is not likely to work well after a significant
increase in transmitter power.

And finally, there IS a federal law about such things, which you will
be in violation of.

I hear that you want more range on your cordless, but modifying a
standard cordless is not the way to go. Try a new 900 MHz cordless.

Dave

------------------------------

Date: Mon, 21 Feb 94 04:07 EST
From: [email protected]
Subject: Re: 900 Mhz Phone Power Output

I'm confused!

Alex Cena <[email protected]> writes:

> There's been quite a bit of disccusion regarding cordless phones so I
> thought it may be helpful to share my experience over the last month
> with my new cordless phone. I have had the opportunity to try AT&T's
> new Dragon, which is a 900 Mhz cordless phone with 1000mw of power.
> It uses spread spectrum technology based on frequency hopping. I
> placed it in the library of our house and here is what I found:

OK, so the AT&T phone puts out one watt (1000 mw). That's certainly more
than the old 49 Mhz ones, which I think were always less than 100 mw.

[email protected] (Bill Mayhew) writes, (Re: VTech 9 "Tropez" and
Sony SPP-ER1 900 MHz Phones):

> The 900DX appears to be fully digital, using the 902-928 MHz shared
> band. Power output is reportedly 0.0005 watts (1/2 mW) according to
> another net reader. I found the effective range to be around 600 feet

So the AT&T phone puts out one watt, but this phone puts out one half
MILLIWATT? Thats a 2000:1 (33 decibel!) difference.

Somehow I am having a hard time believing EITHER spec.

Paul Cook Proctor & Associates
Redmond, WA [email protected] 206-881-7000

------------------------------

Date: Mon, 21 Feb 94 14:12:15 EST
From: Alex Cena <[email protected]>
Subject: Re: 900 Mhz Phone Power Output - Correction

In article <[email protected]>, Bruce Laskin wrote:

>> There's been quite a bit of disccusion regarding cordless phones so I
>> thought it may be helpful to share my experience over the last month
>> with my new cordless phone. I have had the opportunity to try AT&T's
>> new Dragon, which is a 900 Mhz cordless phone with 1000mw of power.
>> It uses spread spectrum technology based on frequency hopping. I
>> placed it in the library of our house and here is what I found:

> 1000mw ... really! ... WOW! -- that's significantly more than the
> 600mw maximum power output for handheld cellular sets! The 600mw
> limit for cellular sets was intended to prevent health hazards, so how
> is AT&T able to use 1000mw? (Most wireless home phones put out no
> more than 0.5mw.)

I double checked since Bruce Laskin was not the only one who has asked
for a clarification. "Its 500mw" compared to the 9100, which has
100mw of power. Sorry for the error on my part.

Alex M. Cena, Lehman Brothers, [email protected]

------------------------------

From: [email protected] (Sean P Peacock)
Subject: Re: Need Information About Telemate
Organization: NETCOM On-line Communication Services (408 241-9760 guest)
Date: Mon, 21 Feb 1994 12:34:17 GMT

The Network Group ([email protected]) wrote:

> I have a client that is using a PC to capture SMDR data and somehow
> import it to a program called Telemate. I need to get any information
> on who manufactures Telemate. I have been unsuccessful in my attemps
> to find this company.

> Any help you can provide is appreciated. Thanks in advance.

Found in ftp://oak.aokland.edu/pub/msdos/modems/tm412-1.zip

Registration Fee : US$ 49 / CAD$ 55

Please send cheque or money order payable to "White River Software"
in US or CAD. Overseas order in money order, please. (Note that the
current postage from US to Canada is $0.40.) For multi-user licenses,
please contact us.

White River Software
P.O.Box 73030
Limeridge Mall Postal Outlet
Hamilton, Ont. L9A 5H7
Canada

We appreciate suggestions and ideas. Most new Telemate features come
from user feedback. In order to provide a mean of support, we have
made an agreement with several Bulletin Board Systems. The following
BBS's will have the latest version of Telemate and a Telemate message
area.

Board Phone Number Network Baud Location
------------------- ------------ -------- -------- ---------------
Land of the Gypsy's 503-297-0626 RelayNet 14400V32 Oregon USA
Late Night BBS 315-564-5700 Genesis 14400DS New York USA
PC Connect 416-733-9052 SmartNet 2400 Toronto Canada
User To User #1 214-492-6565 RelayNet 14400DS Dallas USA
User To User #2 214-492-5695 FidoNet 9600V32 Dallas USA

If you have questions, problems or suggestions, you can leave messages
to 'WINFRED HU' on these Telemate Support BBS's. Echomail conferences
have been set up by these BBS's in FidoEcho, GDNet, ILink, IntelecNet,
RelayNet and SmartNet. Ask your sysop to join them.

For the international editions, you may contact MicroServe Information
eXchange at

Board Phone Number Network Baud Location
----------------- ------------ --------- -------- --------------
M.I.X. BBS +49-4298-30086 UUCP 9600 V32 Lilienthal FRG

In addition, you can reach the author on the following networks:

CompuServe [72070,3515]
InterNet [email protected]

Sean

------------------------------

From: [email protected] (Stefan Bethke)
Subject: Re: VCR and Touch-Tones
Date: Mon, 21 Feb 1994 09:49:56 GMT
Reply-To: [email protected] (Stefan Bethke)
Organization: Promo GmbH, Hamburg, Germany

In article <[email protected]>, [email protected]
(Markus Schlegel) writes:

> I have the following problem: I would like to remote-control video
> equipment that is controllable by infra-red otherwise by means of
> touch-tone.

The German computer magazine {c't} had two projects that might help
you. MacPhone is a Macintosh software answering machine. Using DFT
for DTMF decoding, the software can easily be extended to do whatever
one likes to control remotely.

Another project is a simple interface to send and reveice infra-red
remote control codes from a PC or alike. It's a little interface that
hooks up to the parallel port of the PC.

Both articles appeared in 1993 issues of {c't}. Software is available
by anon FTP from ftp.uni-paderborn.de, ftp.uni-regensburg.de, and
other sites.

It should be easy to use some voice-capable modem to grep DTMF tones
off the phone line and send appropriate code out on the infra-red
sender.

Stefan Bethke

------------------------------

End of TELECOM Digest V14 #95
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