Different ESS systems (DMS-100, 5ESS, etc.)
Scott McClure
Hi all,
I'm moving from an area served by a 5ESS to one served by a
DMS-100 (both are in Pac*Bell land). I found this out thanks to a very
helpful lady in customer service that I talked with when I ordered my
new lines.
Anyway, does anyone know the differences between these switches?
For that matter, is there a list of common switches in use and their
characteristics/features? I know that some RBOCs tend to use certain models
over others.
Thanks,
Scott
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Locklin
>Hi all,
> I'm moving from an area served by a 5ESS to one served by a
>DMS-100 (both are in Pac*Bell land). I found this out thanks to a very
>helpful lady in customer service that I talked with when I ordered my
>new lines.
> Anyway, does anyone know the differences between these switches?
I'm not all that sure, but I believe that 5ESS has a noticable "click"
from the relays after dialing a number wheras DMS-100 is silent in operation.
I'm reasonably sure that there are subtle differences in the timing of the
line scanning (I'm not sure of the tech term; line scanning= when the switch
checks the condition of the subscriber loop), though I'm sure that only a
computer would notice the difference. The specs are in the old BSTJ writeups on
these switches.
Anyone remember the old days when you would pick up a phone on a SxS & actually
have to wait a few seconds for dialtone?
-L
Steve Waddell
>Hi all,
> I'm moving from an area served by a 5ESS to one served by a
>DMS-100 (both are in Pac*Bell land). I found this out thanks to a very
>helpful lady in customer service that I talked with when I ordered my
>new lines.
> Anyway, does anyone know the differences between these switches?
>For that matter, is there a list of common switches in use and their
>characteristics/features? I know that some RBOCs tend to use certain models
>over others.
5ESS (by ATT) and DMS-100 (by Northern Telecom) are two very common CO
Switches used by TELCOS for subscriber service. Another is 1AESS, an
older analog model. (5E & DMS are digital).
For normal POTS service you will see no differance. Features may operate
somewhat differently, but all the normal ones can be there, depending on
the TELCO and their Tariff.
More advanced services are more dependent on the switch. ISDN will be
*very* different, and not available at all from the 1AESS.
Most of the ex-ATT RBOCS will be using ATT & Northern. Other switches
can come from Siemens, Stromberg-Carlson, NEC and others. GTE uses a lot
of GTE switches (surprise). I have no expreience with them but I hear
that they are junk.
You might try BellCore for more info. Start with is...@cc.bellcore.com.
--
- Steve :^> - - - - - - - - - - - - - - -
wad...@iglou.com 10307 St. Rene Rd. voice 502-266-5695
Louisville, KY 40299-4040
"It's a good thing we don't get all the government we pay for" Will Rogers
Matthew P. Downs
>sc...@ryptyde.nix.com (Scott McClure) writes:
You could compare the two with the following documents:
depending upon the switch version:
5ESS TR303 Software version document: AT&T 235-900-308 Issue 2.00 December 1991
DMS Supernode TR-303 Software version Document : NIS A217-2 Issue 01.01 Feb, 1994
There will be many other version of the document for the different software
loads available. You will then need the Bellcore requirements document for
the particular feature(s) you're interested in, in order to compare how they
operate. For example, the 5ESS and DMS TR-303 say they meet the TR-303
requirement for ISDN. BUt one says with this exception and that. You would need
the TR from Bellcore on ISDN to compare this, TR-303 would only be a pointer
to the other TR......
Matt
Bob Haddleton
> I'm not all that sure, but I believe that 5ESS has a noticable "click"
> from the relays after dialing a number wheras DMS-100 is silent in operation.
Actually, that is the 1AESS that has the "1A click" after you finish
dialing. The 5ESS is digital - no relays. My local 1AESS was
converted to a 5ESS some time ago, and I still miss the click (so I
know that I really did dial all of the digits, my phone fakes me out
sometimes). I do like having my ISDN line, though.
--
Bob Haddleton AT&T Network Systems bo...@nwsca.att.com
My opinions are my own, if I could only remember where I left them...
Mike King
Locklin <loc...@phyast.pitt.edu> wrote:
>I'm not all that sure, but I believe that 5ESS has a noticable "click"
>from the relays after dialing a number wheras DMS-100 is silent in operation.
^5^1A
The 5E doesn't have the audible click, though a 1AESS (and 1ESS) will
"click."
--
Mike King [m...@tfs.com] Oakland, CA
John Higdon
> Anyway, does anyone know the differences between these switches?
Supporters of each almost comprise opposing cults. The DMS "seems"
faster and more crisp in its action. Audio paths seem to be set up
faster and the switch is quicker to return busy and audible ring tone
on calls. Some claim that the audio on the DMS is cleaner, although it
has been cleaned up on the 5ESS considerably in the past couple of
years. (When my 5ESS first went in, the voice distortion was painful to
my ear. Either I have become used to it, or it has improved.)
Both switches now have a "1ESS emulation" package that simulates the
features and feel of the venerable WE 1ESS analog switches.
You mentioned Pac*Bell and that is an important factor. Pac*Bell's
implementations of the DMS have been dreadful. When I have used the
same switch in other jurisdictions (such as Contel), the performance
was greatly improved. Pac*Bell apparently has had many customer
complaints when they have cut DMS switches into service. The "company
line" is that the switches are inferior, and use this as justification
for moving toward 5ESS. Insiders tell me that the selection of switches
at Pac*Bell is purely political and when PB got kicked out of bed at
Northern Telecom, it went running to AT&T. As far as the bad
implementations are concerned, I am not clear about who bears that
responsibility. NT people have claimed that PB engineering mucked with
them too much.
>For that matter, is there a list of common switches in use and their
>characteristics/features? I know that some RBOCs tend to use certain models
>over others.
In the US, it seems to be coming down to DMS and 5ESS. I don't consider
the GTD-5 real equipment and is not worth considering. Even GTE is
replacing them.
--
John Higdon | P.O. Box 7648 | +1 408 264 4115 | FAX:
jo...@ati.com | San Jose, CA 95150 | 10288 0 700 FOR-A-MOO | +1 408 264 4407
Henry Wertz
(Bill Mayhew) writes:
>I am pretty sure my home exchange: 216-928 used to be on a 5ESS
>swich. About a year ago, I received a postcard from the local RBOC
>office saying that the switch was being cut over to a DMS-100. I
>found it curious that the RBOC thought it worthwhile to inform
>residential customers of the change, given that most customers
>wouldn't have a clue what Ameritech (then Ohio Bell) was talking
>about.
>
>I noticed a few things after the switch. One is irritating. When
>dialing, there is a noticable cut-through delay on the dial tone after
>keying the first digit. The cut-though was really long at first,
>around 500 mS. Qualitatively, the delay is shorter now. At first,
This could actually be problematic... on the Racal Vadic VA212 I have, it
has a "pulse", "tone", and "autodetect" mode. In autodetect, it dials the
first digit tone, and sees if there's still a dialtone. If there isn't, it
assumes the tone registered. If the tone's still there, it switches to pulse.
That'd be bad if it dialed tone, switched to pulse, *THEN* the switch
recognized the first digit 8-).
(I got this 1200 baud modem at Goodwill because it seemed like a nice
oddity to have around and it was really cheap 8-).
>I found myself re-keying the first digit, thinking it had not
>registered. I'd be curious to see what the stats were for
>misdialed or aborted calls was after the cut-over. I have a
>feeling that a lot of customers just go ahead and dial all seven
>(or more) digits before bothering to listen to the line. I grew up
>long enough ago in an SxS swich exchange where it paid to listen to
>what was happening as you dialed.
>
>Audio quality doesn't seem any different on the new switch.
On our "5ESS" switch.. the voice is okay, but the dialtone sounds
incredibly "dirty"... it just doesn't sound at all pure like it used too. (We
upgraded from a 1ESS to a supposed 5ESS a couple months ago... now it takes a
second or two for the thing to even give a dial tone after you pick up. I
don't know what it *really* is... I don't think it's a real 5ESS is, though...
) It's in Iowa City, Iowa. We have USWest. If you could tell me what it is,
that'd be great.
>--
>Bill Mayhew NEOUCOM Computer Services Department
>Rootstown, OH 44272-0095 USA phone: 216-325-2511
>w...@uhura.neoucom.edu amateur radio 146.58: N8WED
Bill Mayhew
swich. About a year ago, I received a postcard from the local RBOC
office saying that the switch was being cut over to a DMS-100. I
found it curious that the RBOC thought it worthwhile to inform
residential customers of the change, given that most customers
wouldn't have a clue what Ameritech (then Ohio Bell) was talking
about.
I noticed a few things after the switch. One is irritating. When
dialing, there is a noticable cut-through delay on the dial tone after
keying the first digit. The cut-though was really long at first,
around 500 mS. Qualitatively, the delay is shorter now. At first,
I found myself re-keying the first digit, thinking it had not
registered. I'd be curious to see what the stats were for
misdialed or aborted calls was after the cut-over. I have a
feeling that a lot of customers just go ahead and dial all seven
(or more) digits before bothering to listen to the line. I grew up
long enough ago in an SxS swich exchange where it paid to listen to
what was happening as you dialed.
The other difference is that the line polarity reversal is now
about six seconds after the originating party hangs up on you.
I've noticed this from stats my voicemail system grabs. With the
5ESS, the reversal was very quick. I suspect some of the timing
differneces are switch configuration options, while some other
dealys might be due to call setup and handling being processed by a
a separate SS7 channel. The polarity reversal was something like
15 seconds when the DMS-100 first went on line, so there is
evidence that there is some on-going tweaking.
According to some local telco people, the DMS-100 has a lot more
capacity and the capability of implementing many ISDN features of
which our old swich was not capable. Now, if we could only get
those features....
Audio quality doesn't seem any different on the new switch.
Mike King
Bill Mayhew <w...@uhura.neoucom.edu> wrote:
> About a year ago, I received a postcard from the local RBOC
>office saying that the switch was being cut over to a DMS-100. I
>found it curious that the RBOC thought it worthwhile to inform
>residential customers of the change, given that most customers
>wouldn't have a clue what Ameritech (then Ohio Bell) was talking
>about.
[...]
>The other difference is that the line polarity reversal is now
>about six seconds after the originating party hangs up on you.
>I've noticed this from stats my voicemail system grabs. With the
>5ESS, the reversal was very quick. I suspect some of the timing
Hence the notice from Ameritech. If a subscriber has an application
that depends on the reversal, it can be affected. I've heard of
instances where the new switch was configured such that there was no
reversal at all.
Better safe than sorry on their part, even if it confuses a lot of
subscribers. Those who need to be informed will be.
Mark Rudholm
bo...@nwsca.ATT.COM (Bog Haddleton) wrote:
>In article <940913162...@minerva.phyast.pitt.edu> loc...@phyast.pitt.edu >(Locklin) writes:
>
>> I'm not all that sure, but I believe that 5ESS has a noticable "click"
>> from the relays after dialing a number wheras DMS-100 is silent in >operation.
>
>Actually, that is the 1AESS that has the "1A click" after you finish
>dialing. The 5ESS is digital - no relays. My local 1AESS was
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^*
>converted to a 5ESS some time ago, and I still miss the click (so I
>know that I really did dial all of the digits, my phone fakes me out
>sometimes). I do like having my ISDN line, though.
>
>--
>Bob Haddleton AT&T Network Systems bo...@nwsca.att.com
>My opinions are my own, if I could only remember where I left them...
>End of article 4612 (of 4613) -- what next? [npq]
Most of the COs here in LA have 1As and either a DMS-100 or a 5ESS.
When I move, I ask to be on the 1A. I like being able to hear what
my switch is up to. For example, if my call-waiting rings and I choose
to ignore it, I can tell when the second caller gives up, also, when
I'm dialing on my three-way calling dialtone, I get a distinct "click"
when I complete a vaild string of digits. Also, after dialing a vertical
service code (i.e. *70, *72) I do not have to pause before entering
more digits, in fact, I have a lot of vertical service code + phone
number strings in my memory dialer with no pauses at all. DMS 100s
don't allow for that.
*Since when are relays not digital? I tend to think that "digital" is not
really an appropriate term to distinguish a 5ESS/DMS100 from a 1AESS. I
mean, when you think about it, aren't _all_ telephone switches "digital"?
Dial pulses are digital signals, the Strowger step-by-step switch
was "digital." Mechanical yes, but that doesn't mean "not digital."
I think the correct nomenclature should be "solid-state." This would
disclude the 1A by virtue of the reed relays it employs.
-Mark
Terry Kennedy, Operations Mgr.
> *Since when are relays not digital? I tend to think that "digital" is not
> really an appropriate term to distinguish a 5ESS/DMS100 from a 1AESS. I
> mean, when you think about it, aren't _all_ telephone switches "digital"?
> Dial pulses are digital signals, the Strowger step-by-step switch
> was "digital." Mechanical yes, but that doesn't mean "not digital."
> I think the correct nomenclature should be "solid-state." This would
> disclude the 1A by virtue of the reed relays it employs.
The 5ESS transports calls as digitized audio, while the 1A simply switches
the analog audio path around. That's one of the reasons 5E's support ISDN and
1A's don't. Also, it makes digital entrance facilities more economical - to
provide them with a 1A means a channel bank at the CO to turn the lines back
into analog before the switch, while with a 5E you just haul the bits out of
the switch directly.
But I still like the 1A. If we ever get cut over to a 5E, I'm going to make
sure we get 1A emulation if available (we've got a few thousand lines).
Terry Kennedy Operations Manager, Academic Computing
te...@spcvxa.spc.edu St. Peter's College, Jersey City, NJ USA
+1 201 915 9381 (voice) +1 201 435-3662 (FAX)