Main big CO switches?

Main big CO switches?

Post by Lisa nor Je » Thu, 31 Aug 2000 04:00:00



I've seen mention here of various central office large switches,
such as the 5ESS.

Could someone post the principal large switches and their manufacturer?
(Any comments about quality and opinion would also be interesting.)

Thanks.

 
 
 

Main big CO switches?

Post by Diamond Dav » Thu, 31 Aug 2000 04:00:00


There are a lot of central office switches out there.

Two of the most common are the Western Electric/AT&T/Lucent series and
the Nortel DMS series.

Western developed the 1ESS in 1965 and the "modernized" 1AESS in 1976.
Most if not all 1ESS systems in use at the time got the upgrade to 1A
(which, IIRC, was a CPU upgrade). This is a computer controlled ANALOG
switch. These are still in use in many places but are slowly being
converted to fully digital offices.

Western also developed the 4ESS as a toll tandem (though I've heard it
is being used as a local office on a CLEC basis now). First
installation in 1976, last installation in 1999 in suburban Atlanta.
Primarily used by AT&T long distance, it is used in some local cases
such as New York City as a regional/local tandem.

Western also developed the 5ESS switch. First installation was in
1982. It is used primarily in baby Bell areas but are also being used
in independent territory. This is a full digital switch. It can be
used as a local office or a toll tandem (or both). It is sometimes
referred to these days as the 5ESS-2000 or the SM2000 switch.

Automatic Electric (now AG Communications, a joint venture between
AT&T (now Lucent) and GTE) made a number of digital switches. The 1EAX
and 2EAX were developed along the same lines as the 1ESS/1AESS line
(analog switch, computer control). I don't think these are in service
anymore. Last one I ran across was in the Dominican Republic a couple
of years ago. Used primarily by GTE systems, but independents used
them as well.

AE/AG developed the 5EAX (aka the GTD-5) for use within GTE territory.
As far as I know, no other companies other than GTE have used this
switch. It is a full digital switch, but it lacks some things that
most other digital switches have such as ISDN. GTE is phasing some of
these out in favor of 5ESS or DMS-100 switches.

Northern Telecom (orginally Northern Electric, now Nortel) was a
leader in digital switching. Though not the first digital switch, it
was probably the*one that took off. The DMS-10, developed in 1979
(or 1978?) and later the DMS-100, is the bread and butter switch used
throughout Canada and a lot of independents in the US. Nortel has a
large DMS line and is described in detail on their website:
(www.nortelnetworks.com).

Direct URL to the switching page:
http://www.veryComputer.com/

Other switches include the Stromberg-Carlson (now part of Siemens) DCO
switch (Digital Central Office). Used in a number of rural
independents. Siemens makes the ESWD switch and is gaining in
popularity (I've seen Bell Atlantic replace 1A's in Pennsylvania with
ESWD's). Ericsson also has a few digitals here as well as other
smaller ones like Redcom, ITT, Vidar and a few others.

But the majority of switches are Lucents and Nortels. Probably the two
combined make up 3 out of 4 switches in the US. Nortel probably 9 out
of 10 in Canada.

Just my 2 1/2 cents. Feel free to correct if need be.

Dave Perusel
Webmaster - Telephone World
http://www.veryComputer.com/



Quote:>I've seen mention here of various central office large switches,
>such as the 5ESS.

>Could someone post the principal large switches and their manufacturer?
>(Any comments about quality and opinion would also be interesting.)

>Thanks.


 
 
 

Main big CO switches?

Post by Daniel Seagrave » Thu, 31 Aug 2000 04:00:00



Quote:> I've seen mention here of various central office large switches,
> such as the 5ESS.

> Could someone post the principal large switches and their manufacturer?
> (Any comments about quality and opinion would also be interesting.)

The only switches I know of as being BIG, are the 5ESS, Lucent makes
those, and they're hideously expensive, and the Nortel (Or is it someone
else?) DMS-500, which has a similarly frightening price tag.  All we have
around here that I have found are a 5ESS, some DMS-100s, and assorted
remotes.

A 5ESS installation is down the street a little ways - The office is large
and used to be an operator center.  I wonder if I showed up w/ a camera
would they let me take pictures... (Our T-1s run to the office in
question).

Downtown there is a HUGE CO that's supposed to have another 5ESS and a
couple DMS switches.  It used to have a Crossbar 5, according to some
papers I had.  I asked if they gave tours once, and was told that while
they wouldn't let me in, they'd let a friend of mine in because his
company has a DS3.  All attempts thereafter at getting my boss to get a
DS3 have failed. :P

"Confuse, annoy, and DEE-STROY!" -- Jet Wolf | "Nothing Happens." -- ADVENT
"You'd be surprised what you can live through..." -- Anonymous
"...A man can pass his family and his name down through his sons, but it's
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and worst of life in his girls.  A daughter is something far too precious,
and he'll do anything to protect her."
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Main big CO switches?

Post by Lisa nor Je » Thu, 31 Aug 2000 04:00:00


Quote:> A 5ESS installation is down the street a little ways - The office is large
> and used to be an operator center.  I wonder if I showed up w/ a camera
> would they let me take pictures... (Our T-1s run to the office in
> question).

If you just show up at the door odds are you will NOT be allowed in.

However, if you call the company in advance and request a visit, they
may let you in.

The building is probably used for different activities now since the
ESS switch takes up far less space than older technology.  I know
of a four story building that housed a big xbar where the replacement
took up 1/2 of one floor, freeing the rest of the building for other uses.

I've seen (and heard) that you'll find an older rotary dial wall
phone (ie 554) somewhere still in use for testing.  Looks out of place.

 
 
 

Main big CO switches?

Post by Grover C. McCoury II » Thu, 31 Aug 2000 04:00:00


FYI:
Per the "Bell Labs Bible", Engineering and Operations in the Bell
System(1978), the following introduction dates are listed:

Electronic Local Switches
No. 1 ESS                   1965
No. 2 ESS                   1970
No. 3 ESS                   1976
No. 2B ESS                1976
No. 1A ESS                1976

Electronic Toll Switches
No. 1 ESS                   1970
No. 4 ESS                   1976

Oh, and also make that the Siemens EWSD switch...


>  Siemens makes the ESWD switch and is gaining in
> popularity (I've seen Bell Atlantic replace 1A's in Pennsylvania with
> ESWD's).

--

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  physical: 212 Gibraltar Drive
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 **********************************/

 
 
 

Main big CO switches?

Post by John R Levi » Thu, 31 Aug 2000 04:00:00


Quote:>AE/AG developed the 5EAX (aka the GTD-5) for use within GTE territory.
>As far as I know, no other companies other than GTE have used this
>switch. It is a full digital switch, but it lacks some things that
>most other digital switches have such as ISDN. GTE is phasing some of
>these out in favor of 5ESS or DMS-100 switches.

The GTD-5 is quite popular with independents.  My telco has two of
them.  It's true, ISDN was very late, but the usual features like
calling line ID and three-way are all available and work.  GTE had a
lot of trouble with them, but my telco's engineer tells me that they
work fine for the independents that apply the software updates and
maintain them decently.

It is my impression that after the most recent round of mergers and
spinoffs, the GTD-5 line now belongs to Lucent who is maintaining it
but would rather sell you a 5ESS.

--
John R. Levine, IECC, POB 727, Trumansburg NY 14886 +1 607 387 6869

Member, Provisional board, Coalition Against Unsolicited Commercial E-mail

 
 
 

Main big CO switches?

Post by Diamond Dav » Thu, 31 Aug 2000 04:00:00


On Wed, 30 Aug 2000 14:54:06 GMT, "Grover C. McCoury III"


>FYI:
>Per the "Bell Labs Bible", Engineering and Operations in the Bell
>System(1978), the following introduction dates are listed:

>Electronic Local Switches
>No. 1 ESS                   1965
>No. 2 ESS                   1970
>No. 3 ESS                   1976
>No. 2B ESS                1976
>No. 1A ESS                1976

Oh yes, forgot those other ones like the 2BESS and 3ESS. I highly
doubt any are in service anymore.

Forgot to mention that Stromberg- Carolson made the ESC switch around
the same time. Basically their version of a 1/1AESS.

Quote:>Electronic Toll Switches
>No. 1 ESS                   1970
>No. 4 ESS                   1976

Yeah, the 1ESS was also part of the operator system known as TSPS,
which was replaced by OSPS (5ESS technology) and TOPS (DMS-200
technology)

Quote:>Oh, and also make that the Siemens EWSD switch...

OOPS - I always transpose letters. Thanks!

Dave

 
 
 

Main big CO switches?

Post by Macy Hallo » Thu, 31 Aug 2000 04:00:00



+---------------

Quote:> >AE/AG developed the 5EAX (aka the GTD-5) for use within GTE territory.
> >As far as I know, no other companies other than GTE have used this
> >switch. It is a full digital switch, but it lacks some things that
> >most other digital switches have such as ISDN. GTE is phasing some of
> >these out in favor of 5ESS or DMS-100 switches.

GTE/AE's No. 1 EAX and No. 2 EAX machines were hybrid relay/electronic
systems (Who would expect a C.O. from AE without relays?). I lived thru
both under GTE, there we little better than the SxS systems they
replaced. I know of no EAX's that remain in service in this area.

Most of the early EAX's were in service less than 5 years before
being upgraded, often with GTD-5 systems.  GTE knew the digital
designation was required to show the public they were modernizing,
I suspect that prompted the name change from No. 5 EAX to GTD-5.

The accounting life of a C.O. in front of the PUCO is 20+ years,
how GTE justified the early retirement of these office is somewhat
questionable...even to the PUCO, but they did it.

Quote:> The GTD-5 is quite popular with independents.  My telco has two of
> them.  It's true, ISDN was very late, but the usual features like
> calling line ID and three-way are all available and work.  GTE had a
> lot of trouble with them, but my telco's engineer tells me that they
> work fine for the independents that apply the software updates and
> maintain them decently.

I know a couple of very smart people who maintained GTD-5's. They liked
the systems and found most of the problems were with GTE policies
rather than the switch itself.

Most of the GTD-5 capabilities are good.  It's also reliable.
Again, GTE's method of using its services, such as Centrenet/
Centrex are odd (dial 5 for an outside line?) but that's not
a reflection on the system itself.

As for modern services... ISDN PRI service was introduced later to
the GTD-5 than some other switches, but it works well and is widely deployed.

GTE did their best not to install ISDN BRI lines in this area. They
required over 200 BRI lines be on order to even consider adding the capability.
They blamed this on the cost of adding the shelf and software upgrades.

I always felt it was more of a "we really don't wanna do this" addtitude
toward ISDN, which we encounted with many telcos.  Their insistence that
ISDN should be priced as a "premium" service confirmed this.
(ISDN = Innovations Subscribers Don't Need, right?)

Quote:> It is my impression that after the most recent round of mergers and
> spinoffs, the GTD-5 line now belongs to Lucent who is maintaining it
> but would rather sell you a 5ESS.

AG Communications still exists, but seems to be doing other things.

They still manufacture line additions for the switch, but I'm told
new systems are not being installed.

I know that additions are regularly done to GTD-5's in Ohio, but some of
the hardware is purported to come from deinstalled GTD-5 systems.
--

  APK Net, Inc.   1621 Euclid Ave.   Suite 1230    Cleveland, OH 44115 USA

 
 
 

Main big CO switches?

Post by Neil Hyndma » Thu, 31 Aug 2000 04:00:00


Bell Canada Enterprise (the company that owns Bell Canda) use to own Nortel,
but they have recently spun Nortel off.  I think, if I remember correctly,
Nortel no longer produces the DMS system, but now contracts it out to a
company called ExperTECH.  I could be wrong!  But my uncle use to work for
Nortel, designing and trouble shooting DMS systems for bell companies all
around the world, but his division was sold to ExperTECH.

Neil
(I will check into this ExperTECH thing!)




> >I've seen mention here of various central office large switches,
> >such as the 5ESS.

> >Could someone post the principal large switches and their manufacturer?
> >(Any comments about quality and opinion would also be interesting.)

> The main manufacturers of CO switches in the US and Canada are Lucent
> and Nortel.  The #5ESS is manufactured by Lucent (formerly AT&T) and
> the DMS-100 and other variations of DMS is manufactured by Nortel.
> Bell Canada uses almost exclusively DMS switches.

> I've heard that some people think that some of the functions of the
> DMS can be quirky such as delaying the ability to dial when you get
> the confirmation tones (beep-beep-beep-beep) before dialing when you
> select a feature such as per call block/unblock, call waiting *70 etc.
> Other than that I think they are both very capable switches.  Many
> cities such as my own (Seattle) use both though the majority of
> switches here are #5ESS with a few DMS-100 and a few analog #1A ESS
> switches still in service, but are due to be replaced with either
> #5ESS or DMS within the next year.  My CO was recently changed from a
> 1A to a 5E.  The difference that I notice in the change are faster
> switching time, silent switching i.e. no clicks whatsoever.  I also
> notice that the sound of the dial tone seems to have more "white
> noise" in it than it did previously with the 1A.  Also when you remove
> the receiver you immediately hear a dial tone with only the faintest
> click whereas before with the 1A you hear a definite "chunk" as the
> dial tone came on line.  Also, when a called party answers if they are
> on a 5E or DMS you don't hear a "click" either.  Still, I miss the old
> days of switching where each exchange had its own personality.
> - - - - - - - - - - - - - - - - - - - - - - - - - - -
> Joseph Singer Seattle, Washington USA

 
 
 

Main big CO switches?

Post by Macy Hallo » Thu, 31 Aug 2000 04:00:00



+---------------

Quote:> > GTE/AE's No. 1 EAX and No. 2 EAX machines were hybrid relay/electronic
> > systems (Who would expect a C.O. from AE without relays?). I lived thru
> > both under GTE, there we little better than the SxS systems they
> > replaced. I know of no EAX's that remain in service in this area.

> In the 1970s, Bell Laboratories developed a number of electronic
> enhancements for SxS to extend the functional lifespan of them. The actual
> switching may have been still SxS but calls went through front-end
> and rear-end electronic units.  I'd have to look up the specific details
> in old copies of Bell Laboratories Record.

Yep. That's a Director.
We had 'em at a couple of GTE CO's when I worked there.
They "programmed" the old fashioned way, with jumpers.

Quote:> It is hard to believe today, but it wasn't that long ago that
> relays would be cheaper than electronics in certain circumstances.
> For small offices and PBXs, this kept SxS around for a long time.

Many all relay (not SxS) switches were very common in various size ranges.
I worked in several North CX all relay CO's that served will over 30 years
before ultimate replacement. These required even less periodic maintenance
than SxS CO's, but required more care to adjust and repair.

The smallest SxS CO I ever worked on or saw was about 400 lines.
That was about the smallest SxS PBX I recall, though I heard of
smaller ones.

Everything, PBX or CO, that was smaller tended to be all-relay,
crossbar or crosspoint. At least in my experience.

I know that smaller Stromberg XY switches were not uncommmon, though.
These things tended to be installed and forgotten by many small
telephone companies and the military.

--

  APK Net, Inc.   1621 Euclid Ave.   Suite 1230    Cleveland, OH 44115 USA

 
 
 

Main big CO switches?

Post by Lisa nor Je » Fri, 01 Sep 2000 09:15:04


Quote:> GTE/AE's No. 1 EAX and No. 2 EAX machines were hybrid relay/electronic
> systems (Who would expect a C.O. from AE without relays?). I lived thru
> both under GTE, there we little better than the SxS systems they
> replaced. I know of no EAX's that remain in service in this area.

In the 1970s, Bell Laboratories developed a number of electronic
enhancements for SxS to extend the functional lifespan of them. The actual
switching may have been still SxS but calls went through front-end
and rear-end electronic units.  I'd have to look up the specific details
in old copies of Bell Laboratories Record.

It is hard to believe today, but it wasn't that long ago that
relays would be cheaper than electronics in certain circumstances.
For small offices and PBXs, this kept SxS around for a long time.
Likewise, in computers, in some shops pure punched card relay machines
remained in service until the 1980s until hardware and software
dropped in cost enough to justify their replacement.

We take cheap but powerful computers for granted these days, but in
the 1980s technology levels exploded.

 
 
 

Main big CO switches?

Post by Steven Licht » Fri, 01 Sep 2000 10:21:37


Macy M  said:
<<
Yep. That's a Director.
We had 'em at a couple of GTE CO's when I worked there.
They "programmed" the old fashioned way, with jumpers.
 >>

The electronic directors we put in were calls System 7.  They were a rather
strange computer managed system built by IBM and some other companies.  They
took the place of touch tone converters, detection and most if not all
translation.  We had one in an office for over 5 years after it was cut over to
a GTD-5. It appears that Bank of America which owned the equipment and GTE
leased it from had no idea what they wanted to do with it.  Finally we were
told just to dump it, which we did, but not until the area that it sat in was
needed for other use.

Someone said something about a #2 Eax, very few of those were ever put in
service, at least in California.  I only ran into 2 of them, still have the
cassette tape drive; its is SCSI, used to use it to back up my old Apple II
computer that runs the BBS, but now use another H/D, much faster.  

Also still have a rack mounted SXS test train, that works.

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Main big CO switches?

Post by John De Hoo » Fri, 01 Sep 2000 11:37:34



Quote:>I've seen mention here of various central office large switches,
>such as the 5ESS.

>Could someone post the principal large switches and their manufacturer?

Not surprisingly, no one has mentioned the Japanese D60 and D70
switches, designed by NTT for its digital networks and built by
companies like Hitachi, NEC and Oki. You can buy specs here:

http://www.ntt-west.co.jp/open/infoguide/2-1-8b.html

These days NTT gets most of its new switches (especially the smaller
ones) from the likes of Nortel and Lucent, though with considerable
modifications for the Japanese network.
--
John De Hoog   http://dehoog.org

 
 
 

Main big CO switches?

Post by George M. Gra » Fri, 01 Sep 2000 22:22:50


We shouldn't forget the Ericcson AXE-10. It is in service in some
interexchange carriers and even in some LECs. The EWSD has already been
mentioned. on the broadband side, Fujitsu had the FETEX-150.

Having worked on the 36th Street panel office converion to 1ESS in the early
70's, todays switches are positively boring!

George Gray




> >I've seen mention here of various central office large switches,
> >such as the 5ESS.

> >Could someone post the principal large switches and their manufacturer?

> Not surprisingly, no one has mentioned the Japanese D60 and D70
> switches, designed by NTT for its digital networks and built by
> companies like Hitachi, NEC and Oki. You can buy specs here:

> http://www.ntt-west.co.jp/open/infoguide/2-1-8b.html

> These days NTT gets most of its new switches (especially the smaller
> ones) from the likes of Nortel and Lucent, though with considerable
> modifications for the Japanese network.
> --
> John De Hoog   http://dehoog.org

 
 
 

Main big CO switches?

Post by Macy Hallo » Fri, 01 Sep 2000 22:50:18



+---------------

Quote:> We mustn't forget the MITEL GX-5000

> Principally marketed overseas. At one time they were really big in China.
> There's also a good many of them in the UK.

A nice little switch derived from the SX-2000, if I recall correctly.

I recall they were also commonly used in the small village CO's up north
in Canada. I remember an article Mitel put out talking about these and a
sattelite terminal being used for this purpose all over the NWT and Yukon,
to bring modern telephone service for the first time to those areas.
--

  APK Net, Inc.   1621 Euclid Ave.   Suite 1230    Cleveland, OH 44115 USA

 
 
 

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