email@example.com wrote to inquire about Wiring Two Lines on One Jack on 10 Mar 2005 19:21:37 -0800:
Sounds to me like your residence is wired with CAT3 (4 pair) cable instead of the old standard wiring used for phone jacks. It would also seem that your phone jacks are "daisy chained" together instead of each being wired directory from the demark (star topology). I am also assuming that the orange pair is wired to the terminals because there is an open in one of the blue pairs, and someone just grabbed the next available pair as a workaround. Or, they could be used as some sort of intercom / door access system. Please see the attached chart documenting the relationship
Standard wire Cat 3
Tip- Green -----Line 1----- Blue Ring- Red -----Line 1----- White/Blue stripe Tip- Black -----Line 2----- Orange Ring-Yellow ----Line 2----- White/Orange stripe
With that in mind, there is no reason you cannot use the green or brown pair for your second line. Provided that they are not in use at any other jacks. I would highly recommend opening up the other phone jacks, and see if you can find another jack where the orange pair is in use. While that would not be conclusive, it would further substantiate my guess about the orange pair being used in place of the blue pair.
JB The Evangelical Lutheran Good Samaritan Society.