[comp.dcom.telecom] TouchTone

dave@rutgers.edu (12/11/88)

Before the divestiture of the telephone companies by AT&T, Touchtone was
both a registered trade mark, and a registered service mark.  As a trade
mark, it covered the telephone sets which send DTMF signaling.  As a
service mark, it covered the service offered by the telephone companies
who received and processed DTMF signaling.

As a result of divestiture, the trade mark covered AT&T products, while
the service mark covered services offered by seven telco holding companies.
Today, no one owns touch tone... as a trade or service mark.  It has
been dedicated -- which I think is legal jargon for its having been put
in the public domain.

Dave Levenson
westmark!dave

HAMER@ruby.vcu.edu (ROBERT M. HAMER) (06/06/89)

This question has probably been asked before, but as I have been subscribing
for only a short period, I haven't heard the answer.

I am going to move into a new house soon.  Currently, I have two touch-tone
lines.  I use non-AT&T phones (a $10 jobbie, a $20 wall phone, a Pannasonic
(spelling?) cordless, etc...).  Do I need to order touch-tone service and
pay the extra monthly fee to use my touch-tone phones in touch-tone mode?
Does this have something to do with polarity of the lines (I wired the
lines all myself; the new house has 27-year-old wiring; the phones are
HARD-WIRED into the walls; when the phone people come out they are obviously
going to need to install a new network interface box)?

Etc.

Nigel Roberts 0860 578600 <"iosg::robertsn"@iosg.enet.dec.com> (07/12/90)

I called my local British Telecom Sales and Service Department in
Colchester just now. (There's a Freefone number for that (8921), which
is handy seeing I'm in Reading at the moment).

TouchTone (and thus Star Services) is available only on our C.O.
(Colchester 0206) if the number is in the form 5nnnnn or 7nnnnn,
according to the person I spoke to there (Sarah in Customer Sales)

Bearing in mind previous comments on the subject, I asked what type of
exchange served my area (Colchester numbers in the form 39nnnn --
Manningtree used to be an independent exchange with area code 020639
until six or seven years ago when they replaced the Strowger
exchange).

She went away for four or five minutes and to my amazement came back
with the answer. 'It's a TXE-2' she said. Full marks to Sarah for
this.

This leads me to ask a few questions of the DIGEST.

What exactly is a TXE-2? (My guess is that it's a magnetic reed type
exchange).

Is there any way it could support TouchTone? (A BT engineer once told
me that there might be some kind of black box which they can add).

Are there any more features available on the TXE-2 that we are not
being told about?

And does anyone have a guess as to how long it will be before it is
updated to something modern? (I IMAGINE we've got another 19 years of
pulse dialling to put up with, but I hope I'm wrong ...)


Nigel Roberts (on contract at DEC)
Orichalk Ltd;   P. O. Box 49; Manningtree; Essex; CO11 2HQ; England.
Tel.  +44 206 39 6610 or +44 860 57 860 0 (Cellnet)
Fax.  +44 206 39 3148    

johns@scroff.uk.sun.com (John Slater) (07/16/90)

In article <9673@accuvax.nwu.edu>, iosg::robertsn@iosg.enet.dec.com
(Nigel Roberts 0860 578600) writes (with regard to TXE-2 exchanges):

>Is there any way it could support TouchTone? (A BT engineer once told
>me that there might be some kind of black box which they can add).

I believe the TXE-3 was the first BT-installed switch that supported
touch-tone (but you had to ask them to switch it on).

In theory they can bolt a black box on to anything to give it TouchTone
capability, including Strowgers. I don't know whether this is common
practice.

>And does anyone have a guess as to how long it will be before it is
>updated to something modern? (I IMAGINE we've got another 19 years of
>pulse dialling to put up with, but I hope I'm wrong ...)

I hope so too. My understanding is that if it doesn't do TouchTone, it
ain't going to be around much longer (two or three years, max). Then
again they might decide to bolt on lots of black boxes instead of
replacing the switches. :-(

We might be way behind the Americans in offering state-of-the-art
services, but at least the UK network is pretty much the same across
the country (no hand-cranked phones(!), no non-automatic exchanges,
international dialling from _anywhere_, easy and cheap LD access to
the entire country).  I appreciate that these things are rare in the
States, but they are non-existent here.

Now if only they'd offer me itemised billing ...

>Nigel Roberts (on contract at DEC)

That's too bad. We've all got to earn a crust somehow, I suppose. ;-) ;-)


John Slater
Sun Microsystems UK, Gatwick Office

goldstein@carafe.enet.dec.com (Fred R. Goldstein) (07/16/90)

In article <9673@accuvax.nwu.edu>, iosg::robertsn@iosg.enet.dec.com
(Nigel Roberts 0860 578600) writes...

>She went away for four or five minutes and to my amazement came back
>with the answer. 'It's a TXE-2' she said. Full marks to Sarah for
>this.

>What exactly is a TXE-2? (My guess is that it's a magnetic reed type
>exchange).

According to a person here who used to be involved with a large
European switch maker, the TXE-2 is indeed an early electronic-control
exchange using electromechanical matrices.  It's not as "smart" as a
1ESS; the control is more on the order of wired logic than a CPU.

>Is there any way it could support TouchTone? (A BT engineer once told
>me that there might be some kind of black box which they can add).

Probably, if they bothered to insert the registers, but that doesn't
mean they usually do.

I don't know too much more about the beast; the TXE series was an
improvement over Strowger but is certainly not up to today's
standards.  The electronic control probably makes it a lot more
reliable than a traditional WECo crossbar!


Fred R. Goldstein   goldstein@carafe.enet.dec.com 
                 or goldstein@delni.enet.dec.com
                    voice:  +1 508 486 7388 

martin@bellcore.bellcore.com (Martin Harriss (ACP)) (07/18/90)

In article <9673@accuvax.nwu.edu> iosg::robertsn@iosg.enet.dec.com
(Nigel Roberts 0860 578600) writes:

>This leads me to ask a few questions of the DIGEST.

>What exactly is a TXE-2? (My guess is that it's a magnetic reed type
>exchange).

You are correct. The TXE2 is a crosspoint type switch using reed relay
technology.  I believe that the TXE2 design is too old to use
integrated circuits; it uses discrete transistors.  In particular, the
control circuits are all hard wired logic (i.e. not program
controlled.)

>Is there any way it could support TouchTone? (A BT engineer once told
>me that there might be some kind of black box which they can add).

It could be done, but it would be a real hack.  There are two problems
with doing it the "right" way (the right way being to add TT receivers
to the registers.)  Firstly, (see above) the registers are hard-wired.
It would be a real pain to modify them.  Secondly, the fact that
architechturally, the TXE2 is just an electronic step by step system.

This is how a TXE2 works:

When you pick up a phone you are connected through a series of reed
relay crosspoint switches to a relay set.  This relay set connects you
to two things: the local register, and an outgoing junction to the
group switching centre (GSC) - in your case Colchester.  Dial tone is
now returned to the caller from the local register.  When you dial,
your dial pulses go to two places.  Firstly, they are counted by the
TXE2 register. Secondly, they are passed along the junction to the
GSC, where they step switches, get put into a register, or whatever,
depending on what kind of equipment is at the GSC.  In TXE2 parlance,
this junction is known as the 'primary route'.

After you have dialled the first two digits, the TXE2 register will
decide one of three things:

1. The call is going to, or will be routed through, the GSC.  In this
case, the register releases itself from the circuit and the call
proceeds by way of the already connected junction to Colchester.  Any
further digits that you dial are sent to Colchester without further
ado.  The register is, of course, now available for other calls.  This
means that a TXE2 need not store the dialled digits, nor does it have
to translate them or pulse them out to another exchange.

2. The call is to your own exchange.  In this case, the first two
digits you dialled will have been 39.  In this case, the register will
signal the relay set to release the primary route and proceed to suck
in the remaining four digits.  After the last digit has been received,
a completely new path is set up from your calling line circuit,
through the crosspoint switches, through an "own exchange relay set",
and back through the crosspoint switches to the called line circuit.
The own exchange relay set is then responsible for ring current/tone
or busy, as appropriate.

3. The call is to some other exchange to which the TXE2 has a direct
route.  In this case, after the initial digits are dialled, the route
to the GSC will be cleared and a now route set up to the target
exchange.  Subsequent digits dialled will be sent directly to the
target exchange.

The 'dual destination' of your dial pulses is what makes it really
difficult to add touch tone to TXE2's (Finally getting to the point,
here.)  Remember, the TXE2 does not suck in numbers and pulse them out
again later.

Adding TT receivers to the registers is conceptually simple, even if
it is a nightmare from an engineering standpoint.  The problem is that
you have to have some way to convert the touchtones to dial pulses on
the outgoing junctions - remember that TXE2's may be connected to
GSC's that are still strowger, and cannot directly receive TT.

About the best you could hope for would be to connect some kind of
black box TT-to-pulse converter at some point along the switching
train.  But this does not help much, because it takes about as long
for said black box to pulse out a number as it does for you to dial
it.  You might as well have a push button pulse phone.

(N.B. The above description is for TXE2's which have linked numbering
with their GSC.  There are other situations; your milage may vary.)

>Are there any more features available on the TXE-2 that we are not
>being told about?

As you might realise from the foregoing description, the TXE2 is quite
a dumb beast, and adding nifty features does not really come within
its scope.

TXE2 ringback used to be 1267, sometimes 1267105.

>And does anyone have a guess as to how long it will be before it is
>updated to something modern? (I IMAGINE we've got another 19 years of
>pulse dialling to put up with, but I hope I'm wrong ...)

TXE2's are pretty reliable, I think.  Seeing as how yours is only six
or seven years old, it might be around for some time, unless either
the requirement for lines goes up dramatically (TXE2's only handle
about 3-4000 lines) or if it was second hand when it was put it -
maybe as a stop gap measure.  You never know with BT.  Why not call
your friend Sarah?


Martin Harriss
martin@cellar.bae.bellcore.com

julian@bongo.uucp (Julian Macassey) (07/18/90)

In article <9784@accuvax.nwu.edu>, johns@scroff.uk.sun.com (John
Slater) writes:

> We might be way behind the Americans in offering state-of-the-art
> services, but at least the UK network is pretty much the same across
> the country (no hand-cranked phones(!), no non-automatic exchanges,
> international dialling from _anywhere_, easy and cheap LD access to
> the entire country).  I appreciate that these things are rare in the
> States, but they are non-existent here.

	But in the UK you have two telephone companies (BT and Hull)
and you have two Long Distance Carriers (BT and Mercury). Here is the
U.S. we have over 1,000 telephone companies - some with about 300
subscribers.  Also we have a ton of Long Distance companies - I would
guess over 100.

 There are three major Players, AT&T, MCI and Sprint and tons of
others including Cable and Wireless. BT also runs a packet switching
company here (BT Tymenet). There a few packet switchers which are
seperate from LD carriers even if they are owned by them.

	So the ancient stuff still around tends to be owned by the
"mom and pop" operations. Some of these "companies" have mom as the
operator and business office and pop as the CO tech and outside plant
lineman.  The "CO" is often in the back of the house.

> Now if only they'd offer me itemised billing ...

Hull Telephone has offered it for a few years.


Julian Macassey, n6are  julian@bongo.info.com  ucla-an!denwa!bongo!julian
N6ARE@K6IYK (Packet Radio) n6are.ampr.org [44.16.0.81] voice (213) 653-4495