Talk:Telephone exchange/Archive 1

555-test
During the mid 1980's to late 1980's in America in my hometown of Parma, Ohio, there was a "prank" which some people did at a public phone. They would dial 555 then the last four digits of the phone number that appeared on the public phone. Let the phone ring once. Then they would hang up and leave. This would then cause the phone to ring a few seconds later. Of course no one was on the line. This 555-test was also capable of being executed from a private house phone. To the best of my knowledge this 555-test longer works as described.

Can other people please provide further details on the 555-test? — Preceding unsigned comment added by 172.166.104.93 (talk) 12:54, 17 September 2004 (UTC)


 * Many central offices of specific types had a similar arrangement whereby the dialing of a specific 3-digit code followed by the last 4 digits of one's own number would result in the line being rung back. These were test numbers, intended primarily for engineers and installers in the field to use to test and adjust telephone ringers without needing to tie up an operator or other engineer.  The actual 3-digit code which was used varied from one office to another - There was no fixed code, but obviously it had to a code which was not in use as a local exchange prefix in the area concerned.  146.90.55.170 (talk) 19:35, 16 October 2012 (UTC)

Wrong statement removed
I removed the following because it's wrong:

"In 1971 the computerized switching system for telephone traffic was invented by Erna Schneider Hoover and replaced existing hard-wired, mechanical switching equipment."

"Computerized" or stored program control (SPC) switching was put into practice as early as 1958 with the early ESS prototypes that Bell Labs made. If one reads the Hoover patent (US Pat. No. 3623007) it can be seen that Hoover didn't invent SPC switching but rather came up with a method for process priority. This is still used today and was an important development, however the above statement is wrong.

sam 14:38, 22 September 2004 (UTC)

Ringdown method
My source for the Ringdown method (a chain of manually operated long-distance switchboards) is http://www.du.edu/~jcalvert/tech/phones.htm My source for the 2-hour wait time to request and schedule a cross-country toll call in 1943 was my mother who told me about calls she made between western Pennsylvania and California which in todays money would cost about $500 for each call. Greensburger 06:12, 3 September 2006 (UTC)

Phone number trivia
In the interests of relevance, brevity and international view, the whole section should be moved to telephone number. Jim.henderson 13:49, 19 October 2006 (UTC)

Absent objections, it is done. Jim.henderson 06:28, 28 October 2006 (UTC)

Are you talking about just the phone number section? I concur, if so. Rarelibra 00:25, 29 October 2006 (UTC)

As you see, that's what I did. The section sits uneasily in its new home and requires work to integrate it there, but at least now it's uneasy where it belongs, rather than out of place. Jim.henderson 01:17, 29 October 2006 (UTC)

How to find the location, the community for a USA area code and exchange
Where around the web is there reliable information as to what location, what community a USA area code and exchange is designated? —Preceding unsigned comment added by Donwarnersaklad (talk • contribs) 16:24, 4 September 2007 (UTC)
 * See List of NANP area codes for the former. Jim.henderson 12:13, 8 September 2007 (UTC)
 * Try localcallingguide.com and telcodata.us - either should be able to turn an area code and three-digit exchange prefix into a town name. Better yet, the primary sources - nanpa.com (US) and cnac.ca (Canada) - have a list for each area code which indicates which exchange prefix is which village. K7L (talk) 03:41, 2 June 2013 (UTC)

The Nuremberg Trials telephone exchange
Could anyone please provide more context about the image on the right? I don't understand what's depicted, and I cannot see how it relates to the Nuremberg Trials. -- Ddxc (talk) 06:09, 18 November 2007 (UTC)


 * It's a short clip of activity at a typical manual telephone exchange. In particular it happens (or at least claims) to be the exchange supporting the Nuremberg Trials. Bellhead (talk) 04:10, 19 November 2007 (UTC)


 * Well, then this is idiotic, it's not sourced at all. Changing the caption to reflect the little we do know about it. —Preceding unsigned comment added by 67.180.38.221 (talk) 17:36, 27 November 2007 (UTC)
 * If you would bother to watch the original movie, stated as the source, you should have understand... That's what sources are for. --Alex:Dan (talk) 18:42, 6 January 2008 (UTC)

Paste template
Someone has indicated that this article is pasted from an unidentified source. Can't be sure without an identification, but I've seen it grow over the years and think the opposite is more likely. Anyway, seems to me the flag should be either substantiated or taken down. Jim.henderson (talk) 05:10, 12 August 2008 (UTC)


 * Ah. I had looked only at the result of the insertion of the template, not the edit comment which cites this page.  But notice, it's a British site, whilst the contents reflect the American biases of our article, which I know are original here because I, ahem, inserted some of them myself before my understanding broadened outside my own country's experience.  So, no, unless someone's got more solid evidence to offer as to who pasted from whom, it appears to be more appropriate to accuse someone of stealing from Wikipedia (though, why steal what's offered for free???) than vice versa.  Jim.henderson (talk) 04:01, 18 August 2008 (UTC)

Then, I think you're true, so I do the removing. If nobody takes the decision it would remainforever (laugh). Almeo (talk) 20:22, 8 December 2008 (UTC)

That's not a DMS-100
That picture is not a DMS-100. DMS-100's are sh*t brown with green lettering, do not have bay doors in front, are not installed on false flooring with 110/220 AC power, but rather earthquate mounts (floor to ceiling ramsetted into concrete), have overhead cables, lights on the front cables at the back, have lines and therefore cable trays, sit beside main distribution frames, have associated carrier equipment and 48VDC bus bars over the bays. This picture does not appear to be a telephone switch at all, but rather computer cabinets. Perhaps someone at Nortel or from a phone company can donate a picture of a real DMS-100. Unless someone can vouch for this picture (and explain how a DMS-100 can possibly be hidden somewhere inside these computer cabinets), I will remove it. — Dgtsyb (talk) 09:22, 19 April 2009 (UTC)


 * I've seen a dozen DMS-100 offices all in northeastern US and none of this color. However I work in a DMS-100 that sits on false flooring with AC wiring as well as DC.  Most circuit packs are exposed in front, but some are in cabinets much like the ones illustrated, with similar doors.  The MDF is three floors below, and CXR five floors above.  So, no, I don't find it unbelievable that the front parts of a French DMS-100 could look like this with the colors customized to a user's more refined taste.  Jim.henderson (talk) 04:22, 23 April 2009 (UTC)


 * Well, then, maybe you could take a picture of yours 'cause this ain't no DMS-100. With that color, if it is a Nortle switch at all, it is an SL-100 (reeally beeg PABX for anyone that doesn't know what that is) not a DMS-100. — Dgtsyb (talk) 04:45, 23 April 2009 (UTC)


 * It's European equipment practice. EMC (Electro Magnetic Compliance) regulations introduced in the mid 90's mean that kit has to be housed in racks with doors. Most European telcos no longer use building DC distribution and so kit is either 220vAC or 50vDC with a rectifier provided per suite. I've seen two DMS-100s in London in the colour and equipment practice shown. 86.185.37.22 (talk) 17:47, 17 December 2010 (UTC)

Introduction
In the field of telecommunications, a telephone exchange or central office houses equipment that is commonly known as simply a switch, which is a piece of equipment that connects phone calls. It is what makes phone calls "work" in the sense of making connections and relaying the speech information.

I disagree with this definition. First, a central office is not a telephone exchange. A central office is used to operate telecommunications equipment, not exclusively telephone switches. I suggest the following wording:

A central office is the physical building used to operate telecommunications equipment.

Next, When referring to a switch (more accurately, a telephone switch), we are referring to a system, not just a single piece of equipment. I recommend the following wording:

In the field of telecommunications, a telephone exchange or telephone switch is a system of electronic components that connects telephone calls. Teglin 01:48, 29 August 2006 (UTC)