Talk:Plain old telephone service

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On POTS and PANS[edit]

A note, since I don't feel confident enough to edit the article to add this directly. While researching "POTS" in Google and Google Books I discovered something rather interesting. People referred to both POTS and PANS ;-)

That said, the modern day uses of PANS cite it as "Pretty Amazing New Stuff" or "Positively Amazing New Stuff". What's funny is that back in Australian/Commonwealth records, they say "Peculiar and Novel Services". That, in my mind, shows the genesis of POTS and PANS. It was always a retronym, but it first conveyed how POTS was more understandable than PANS. Thirty years later, PANS are cool and POTS went from "plain old" reliable to "plain old" boring. ;-) I wonder if there are other less formal mentions of POTS and PANS that predate 1975-6 or so.

Power Available to a POTS Circuit[edit]

What kind of watts and amps move over these lines?

I don't know about watts and amps, but typical phone wires operate with -40vdc on them when idle (negative voltage impedes oxidation/corrosion), and in the area of -22vdc when 'off-hook.'

Ring voltage is about 110vac in bursts. This was originally meant to actually power the classic telephone ringer bell, but today's phones look for that AC signal to turn on thier solid state ringers. On a side note, Caller ID is transmitted between the first and second ring signals.

DSL, T1 and other data circuits typically operate at a higher voltage, from 90-220vdc.

On a dry day, you can handle bare telephone wires and the -40vdc does not pull enough amperage for you to feel it, though you will get a good tingle if you are in contact with a good ground. Even ungrounded, ring voltage will get your attention quite well.

Hope that helps some.


I'm not sure where the above mentioned -40vdc comes from but I can tell you that virtually all telephone company equipment is powered by -48vdc (forty-EIGHT) power plants located at the telephone company central offices. It is possible that the line voltage FROM the equipment is different than the -48 INPUT voltage. It is also very possible that the voltage MEASURED on the line in a home is much less than the voltage PUT on the line in the central office because of the loss in the circuit. Bellhead 00:24, 25 December 2006 (UTC)

Nominal values as sent from the CO: DC/battery -48vdc, and Ring 90vac. These values can be lower at the jacks in you house due to volt drop in the possible miles long wire from the CO to your house. DC/battery is 6-8 vdc when off hook. My DSL line certainly has standard -48vdc CO voltage. In alot of cities and burbs POTS lines are likely not going all the way back to the CO. There will be digital Pair Gain going on where the POTS lines will originate from the Pair Gain equipment much closer to the customers being served. 66.114.93.6 (talk) 05:13, 25 July 2011 (UTC)
Added a section heading. Anyone who can improve it is welcome, Regards, PeterEasthope (talk) 01:48, 12 May 2011 (UTC)

Merge with PSTN?[edit]

POTS stands for Plain Old Telephone Service and has been used for many decades. It is a plain old analog phone line to connect to a plain old telephone and the technical parameters that made that happen.

PSTN stands for Public Switched Telephone Network and has been used for a shorted period of time. It primarily describes, as the name suggests, the really big picture of calls being connected (switched) throughout the country and the world. It is not a specific technology but thousands of technologies that work together to get a call from one place to another — Preceding unsigned comment added by Foggieday (talkcontribs) 18:06, 23 September 2013 (UTC)

Isn't POTS just a popular synonym for PSTN? —The preceding unsigned comment was added by AZuliani (talkcontribs) 18:57, 1 February 2007 (UTC).

PSTN decribes the overall networking, while POTS describes the specific voice grade service provided to customers. I see no reason for a merger.--Donovan Ravenhull 20:54, 1 February 2007 (UTC)

POTS describes a form of telephone service which includes physical standards and features and is an artifact of maintaining compatibility in the modern communications network. PTSN is an all-encompassing term and not very descriptive. POTS is specific and detailed and can stand on its own. Snafflekid 22:14, 2 February 2007 (UTC)

    • Identifying an unused POTS jack with its phone number:

If you have a POTS jack, and you do not know what phone number is associated with it, you can plug in a phone to it and dial your cell phone, so you can identify the phone number. You can also use a special number that your local phone company uses, to get an automated response that repeats the phone number that your calling from. The local phone company does not normally give out this number - does anyone know what number that is for local Verizon, in New York ? —Preceding unsigned comment added by 65.198.119.131 (talk) 16:21, 10 January 2008 (UTC)

The term "POTS" has never been used by any telephone company I am familiar with, and I worked for Bell Canada for 4 years, who shared terminology and technology with AT&T until its breakup. The first time I heard "POTS" I asked the speaker to explain. He said first read it in a Time magazine article. There you go! Because Time magazine used it, it's legit! Nonetheless, "POTS" a coloquialism for PSTN. That said, it should be merged. Stephen M Brown (talk) 17:39, 21 August 2009 (UTC)

I strongly disagree. I've been in the industry for 25 years and use the term "POTS" all the time. My colleagues are very familiar with it too. For example, the term "POTS line" is frequently used to specify a type of phone line (and its associated services) and to differentiate it from an "ISDN line", a "CENTREX line", a "PBX line", etc. Granted, it is not a marketing term and is probably not commonly understood outside the industry. Snafflekid summed it up well (see above). Bellhead (talk) 15:27, 27 August 2009 (UTC)
Is there a chance that the term "POTS" arose in AT&T Bell culture after the 1959 Bell Canada/AT&T split and Canadians didn't encounter it so much? It's pretty much the one and only term used between telecom people for a traditional phone line in the U.S. I've had to deal with SBC/AT&T (local RBOC), GTE, and CLECs since the mid-1990s, and they all refer to traditional telephone signals as POTS and "POTS lines", to distinguish those lines from proprietary PBX signalling, ISDN, PRI, and channelized T1, all of which were running on nearby pairs also, and the last three of which were all considered PSTN here also, at least by the terminology we used: they all went right back to the telephone central office, all had phone numbers, and all could take calls. POTS was the kind of PSTN service that you could hook a normal telephone to. For Stephen Brown: Are ISDN or PRI talked about as being "PSTN" in Canada? --Closeapple (talk) 15:42, 28 August 2009 (UTC)

please don't merge PSTN with POTS. instead, PSTN should include POTS as a type of connection; that being purely analog; but PSTN also inclues, for example, fiber optic connections, which are digital.

oh, and for the record, since nobody seems to know this anymore except some of us old Phreaks:

POTS has 3 main components: 1. dc loop. originally not to exceed 10 ma at 48 volts. when active (circuit closed, off-hook) from a FXS, FXO provides dialtone. 2. duplex Audio. what you say and what you hear. superimposed upon the DC loop 3. Ringing voltage. low frequency AC (20-25 hertz in the US, originally 96 Volts, or twice dc loop voltage). Originates at the FXO. can only happen when the DC loop is open on the FXS.

Also, the wiki here links to pages that define FXO and FXS. Those pages define FXO and FXS incorrectly, as each other; but FXS is mis-labelled as a "foreign exchange station". None such exists. It's "foreign exchange subscriber".

reference this page: http://www.dceexpress.com/FXS_FXO_Discussion.htm or ask Steve Wosniak. Speaking of the Wos, the wiki page on blue boxes has so much better, well-sourced information about the telephone; if you ask me, this page, and PSTN should be merged into it. —Preceding unsigned comment added by 66.150.46.254 (talk) 17:51, 4 January 2010 (UTC)

Combining the old with the new telephonic technology[edit]

As and adendum, I can testify first hand that my 1915 Western Telephone candle stick phone still works even after I switched to FIOS fiber optics services via the POTS 4 wire telephone copper lines. To put it another way, I can call my wife from my 100 year old candle stick phone from my home over FIOS to her mobile phone with reasonable quality. It does sound like an antique phone, but its good enough. Alexander Graham Bell would be proud Im sure. —Preceding unsigned comment added by TmasAv8r (talkcontribs) 20:52, 29 November 2010 (UTC)

Long after AG Bell died
How do you dial? Bouncing the hook-switch at the right rate? Or, does your wife just call you? — Dgtsyb (talk) 22:21, 30 November 2010 (UTC)
That image is of a 1920's phone. The 1915 models did not have a dial. — Dgtsyb (talk) 01:05, 1 December 2010 (UTC)
Some telephone companies were dial by 1915, but these were mostly independents as the Bell System only began deploying dial exchanges in 1919. I presume then this Western Telephone was not Western Electric, Bell's manufacturing arm. K7L (talk) 01:53, 30 December 2013 (UTC)

Implications of Technology Development

Speaking of combining old with new telecom technologies, Internet and data center firms have gone on record, according to overseas media sources such as "The Guardian", to point out that our Internet backbone is insufficient for the increasing emphasis placed on multimedia usage. Internet users in the UK and elsewhere have been encouraged to scale back on YouTube and other bandwidth-heavy uses to ward off network outages. With phone and business systems increasingly Internet based (VoIP, cloud computing, etc.), how do these trends bode for long-term reliability? Moreover, it has been known since the 1800s that a solar flare or CME (coronal mass ejection) can knock out such services --- the so-called Carrington Effect --- with serious consequences. Telecom and electric infrastructure in the US is aging and vulnerable to man-made and natural threats and, less commonly appreciated, so too are the data centers that power the Internet. What, if any, actions are being taken to safeguard our communications networks given how heavily dependent our economy, national security and personal lives have become on this technology? For example, is it wise to concentrate and consolidate operations to rely on a particular technology or are are we better off making an intentional effort to "layer" a level of redundancy --- i.e. discrete components and systems, both analog and digital, old and new, networked and non-networked? — Preceding unsigned comment added by 96.41.118.199 (talk) 21:41, 15 September 2011 (UTC)

48vdc battery back up[edit]

I am increasingly becoming aware that generators are run at modern COs when the power fails these days. 66.114.93.6 (talk) 08:44, 28 March 2012 (UTC)

The battery is still there. It takes time to start a generator and all calls would drop in those few seconds. The generator recharges the battery. K7L (talk) 01:56, 30 December 2013 (UTC)

Carrier list[edit]

This is very US centric

July 2013 SimonMWatts (talk) 13:35, 22 July 2013 (UTC)

I've removed it. Wikipedia is not a directory listing and it adds nothing of value to the article. K7L (talk) 23:51, 29 December 2013 (UTC)