telephone wiring FREE cabling and networking Helpdesk
 Question by steven lords posted 20 Mar 2004
 telephone wiring
I noticed that the some modular cords
are cross wired pin 3 on one end goes to
pin 4 on the other end and 4 on one end
goes to pin 3 on the other end and cables
are pined 1 to 1.
does it matter if the wires get crossed
in the cables? I have tried both and they
work ok.
 Answer by Joseph Golan posted 30 Mar 2004
Dear steven,

The reason it works is because most analog telephones today incorporate a polarity guard within the set which is needed to get a touch-tone type dial to work. Older equipment did not include this circuitry which required then the proper polarity on the line cord.

Digital sets for behind PBXs do require, for the most part, the line to be polarized in order for the set to function. Those cords must have the pair reversal you are refering to.

Joseph Golan, RCDD

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