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AE 40/Modular cable wiring

Started by 19and41, January 23, 2015, 02:46:31 PM

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I am starting to set up my phone to operate with my VOIP unit and I need to find out what is the correct wiring from the plug contacts to the terminals in the phone.  I can't go by the wire color because all the wires in the cord are silver.  I basically need to know the plug contact position to which terminal.  I would greatly appreciate the help. 
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke


It really doesn't matter anymore, frankly.
The two center pins on a standard RJ11 (single line, 2-wire), RJ14 (dual line, 4-wire), or RJ25 (3 lines, 6-wire) are always the first line in use. If they are colored, red should be ring, and green should be tip.   However, many VoIP ATAs swap the polarity right on the jack, so that people can just use a standard modular cord to plug that into an existing wall phone outlet to get the right polarity on all other jacks.  But, otoh, many do not.
In the end it really doesn't matter, because most ATAs don't connect one side (tip) to the earth ground anyways and the line is therefore floating.
Even modern installations of wire-line telephone service from the phone company are not guaranteed to be traditionally polarized, by some sources I have seen.

Inside most traditional phones of US origin, the two line connections are labeled L1 and L2.   Historically, even WECo switched the meaning of them.  Before the 1950s it was usually  L1 = RING, L2 = TIP.  But with the 500-series, it became  L1=TIP (green), L2=RING (red).

For a few historical telephone types polarity did matter, such as the early touch tone instruments in the 1960s.  The tone dial contained a transistor which requires proper source polarity to operate, and therefore these set needed to be connected in one way only.  Later sets contained a diode bridge working as polarity guard, which automatically switched the polarity when wrong.


Thanks for the fast response!  The cord used with mine has 3 leads and all are connected.  the cord has no color code and I will do continuity checks to try to get the right ones.
"Any sufficiently advanced technology is indistinguishable from magic."
— Arthur C. Clarke