Talk:Telephone hybrid

message: 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.
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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)
replies: text: 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)
thread_title: Telephone hybrid

message: 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)
thread_title:  Merge proposal 

message: Hello fellow Wikipedians,
I have just added archive links to  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
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thread_title:  External links modified 

message: 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)
replies: text: 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)
thread_title:  VoIP being "inherently four-wire" and "[containing] hybrids to perform the required conversion"?