Talk:Telephone hybrid

Telephone hybrid
So many errors:

> The fundamental principle is that of impedance matching.

No so. The main function of the Hybrid is to balance out the Receive and Transmit directions by means of an Inductive Bridge.

This has nothing to do with impedance matching (both the microphone and earpiece could have been designed for 600 ohms).

> hybrids are also called "line echo cancellers"

That is not their function in an Analog phone. Their function is to dramatically reduce the level of the users own voice in the earpiece so that they aren't deafened when they talk. Much work went into finding the correct "Sidetone" volume to encourage people to talk at the correct level.

An Echo Canceller works by inserting the necessary delayed signal(s). Nothing at all to do with Hybrids.

This is all basic stuff to be found in a "Telephony 101" text book.

However I won't try and edit the main page, because it will (as always) be reverted by a know-nothing mod.

--

There was an editor's note that requested a re-write of the introduction to better explain the topic for a person not familiar with the field. So I have done that. Took the opportunity to clean and expand the rest of the article. Stevechurch2 (talk) 02:48, 22 November 2010 (UTC)

I've taken the plunge to re-write this entry. It was marked as a stub. It seemed dusty, inaccurate, and with obsolete and irrelevant information. (Frequency shifters are long gone, for eg.) There were plenty of relevant Wikipedia articles that weren't referenced. Some gratuitous promotional stuff was here. Codecs and hybrids were conflated. The comments below had yet to be addressed. Etc. If the article stands, I'll probably come back later to add a drawing or two and polish the text. Open to any suggestions. Stevechurch2 (talk) —Preceding undated comment was added at 00:06, 26 December 2008 (UTC).

I'm sorry but isn't a telephone hybrid a more generic device to separate the incoming and outgoing audio that would otherwise be carried on the same signal? This seems consistent with the first statement in the article then it goes off on a long tangent about television and radio stations. I think the most common use of these is to put signals on fiber for long distance. Servingsper 03:02, 30 July 2006 (UTC)


 * There are hybrids in every phone and line card and they are discussed in the hybrid coil article. Perhaps that one should be updated, and this article, which is written from a broadcasting POV (see its use of "normal") should clarify that it is discussing a special case.  Jim.henderson 15:06, 12 April 2007 (UTC)

I agree with the Jim.henderson remarks. In addition, the special case discussed goes on a further tangent by delving into an esoteric method which might improve a telephone audio hybrid. So, there is scant content describing basic principles and function. —Preceding unsigned comment added by Fubartu (talk • contribs) 10:08, 14 December 2008 (UTC)

People Discrimination is not legal and against Wikipedia rules
I noticed that some editors (see at History of this page) discriminates Latin American engineers and researchers. Frequently Oscar Bonello of Argentina is discriminated although he is a Fellow member of AES, New York. He is probably the most respected researcher in Audio Engineering and Acoustics in Latin America. He teaches at several universities with thousand of graduated engineers or doctorate students. If you are not convinced, please do a test. Go to the AES website (www.aes.org >> awards) and get a list of Fellow members. Take a few names, of well known researchers (all with the same FELLOW degree). Then go to Wikipedia using the “Google search option” and search for names between quotes; you will find:


 * Leo Beranek He has 265 entries in Wikipedia
 * James Moir He has 98 entries
 * Robert Moog  He has 166 entries
 * Ray Dolby He has 45 entries
 * Oscar Bonello He only has 15 entries

Then when an editor erases any contribution of Bonello as “promotion” please note that he lies; it is a simple act of discrimination, that is unfair and privates the Wikipedia readers of knowing his important contributions. I ask to his many past students to edit articles to help that the Latin American Science and Engineering will be known at the level it deserves. RobertTanzi 200.61.154.180 (talk) 05:28, 11 March 2009 (UTC)


 * Please remember to read Talk_page_guidelines, and if you have time, the rest of that article including the part about signing with your account name. Lacking competence, knowing nothing of the fellow, I shan't address the question of whether this particular person, no doubt worthy, should have a link in this particular article to his Wikipedia biography.  I do wonder what being a "Fellow" of some particular learned society has to do with this article, and what the just deserts of Latin American Science and Engineering have to do with it.  I also wonder what law is involved.  Is this a law of Argentina or some other country, or is is some article of international law?


 * As for Google tests, why should Wikipedia do something about that? The encyclopedia has several purposes, but justice for famous people, even famous people of whom I have not heard, for example about half the men on your list,  is not prominent among them.  As an aside, I notice that Latin American languages are not among those that have an interwiki link in this article; perhaps someone who knows relevant languages should work on that lack. Jim.henderson (talk) 06:30, 11 March 2009 (UTC)

Merge proposal
Someone tagged a proposal to merge telephone balance unit into telephone hybrid. As near as I can tell when looking at sources, the TBU is a thing used pretty much only in radio stations to connect in phone calls. I see no evidence that it's a British/American difference for the usual telephone hybrid. Does anyone have better info on this? Dicklyon (talk) 18:59, 13 December 2012 (UTC)

I propose that the telephone balance unit article be deleted. It contains factual errors and the reference to balun is irrelevant and confusing. TBU (a term that I am unfamiliar with) could then be redirected to telephone hybrid which already covers the subject. Old Aylesburian (talk) 09:36, 3 February 2014 (UTC)

Agree with deletion of telephone balance unit Constant314 (talk) 13:11, 29 June 2014 (UTC)

External links modified
Hello fellow Wikipedians,

I have just added archive links to 2 one external links on Telephone hybrid. Please take a moment to review my edit. If necessary, add after the link to keep me from modifying it. Alternatively, you can add to keep me off the page altogether. I made the following changes:
 * Added archive https://web.archive.org/20080918091004/http://www.aeq.es:80/eng/pr_th02ex.htm to http://www.aeq.es/eng/pr_th02ex.htm
 * Added archive https://web.archive.org/20081222180031/http://www.comrex.com:80/products/hybrids.htm to http://www.comrex.com/products/hybrids.htm

When you have finished reviewing my changes, please set the checked parameter below to true to let others know.

Cheers.—cyberbot II  Talk to my owner :Online 18:44, 8 January 2016 (UTC)

VoIP being "inherently four-wire" and "[containing] hybrids to perform the required conversion"?
The Internet path between my laptop, and between my smartphone when it's on our home Wi-Fi network, and the Internet consists of:


 * Wi-Fi to the Wi-Fi-equipped HomePNA adapter;
 * HomePNA to the room containing the ADSL2+ modem;
 * Ethernet from the HomePNA adapter in that room to the ADSL2+ modem;
 * ADSL2+ to the local central office;
 * Optical fiber, probably, from the CO to my ISP's facility;
 * Possibly Ethernets inside the ISP's facility;

and then you have whatever goes from there to the other Internet peer, most of which is probably fiber plus Ethernet. The only four-wire stuff in there is the Ethernets.

VoIP is just "voice over IP", and IP doesn't require four wires, so I don't see how VoIP is "inherently four-wire".

As for the "required conversion", if we're talking about analog telephones connected through an analog telephone adapter rather than, say, Ethernet-based VoIP phones, the "conversion" is digital-to-analog on one side and analog-to-digital on the other side, not converting between a four-wire analog signal and a two-wire analog signal. The same, BTW, probably applies to line cards if they're converting between classical circuit-switched digital telephone circuits and an analog local loop.

Perhaps a hybrid is needed to connect the analog signals coming out of the digital-to-analog conversion to the two-wire local loop, but, if so, it sounds as if it's separate from the conversion. Guy Harris (talk) 21:48, 17 September 2017 (UTC)


 * Unless "four-wire" in this context means "the voice travels independently in both directions", in which case that's what it should say - the key isn't the number of wires, the key is that RTP packets either carry voice from A to B or from B to A, so A doesn't receive packets containing the stuff they're saying and B doesn't receive packets containing the stuff they're saying, and you don't have to subtract that out. Guy Harris (talk) 23:14, 17 September 2017 (UTC)