In article ,
"TWayne" wrote:

More than likely, all you need are the green and red wires.
The black and yellow wires would be used for a second line
if you had one. In a normal residential system, they are
not used, even though they may be hooked to terminals as
if they are.

A telco will NEVER use the yellow and black lines for a
second line with a normal RJ-11 installation. Those are
for lights and grounds in key systems, etc..

You are wrong. This is very common in residential installations.
People have a second line for the kids or whatever and it goes
on the yellow and black wires.

You can't read: READ what I said: "A telco will ... ". Using
those wires for a phone line can of course be done. ANY wires
could be used. But you'll never get a telco to work on them ever
again; all they would offer to do would be to rip it out and
replace it with properly wired system.

You, kind sir, are mistaken.

The yellow/black pair in the old "light olive green D-Station Wire" was
most certainly - and commonly - used to provide a second line within the
same cable (along side the red/green pair). This is true whether in a
residential or commercial application.

This practice was enumerated in the BSPs (Bell System Practice)s.

A telco will - and does - work on such a two-line arrangement to this
day. It's "legal", proper and [ta da!] works just fine.

Up your reading comprehension skills.

The OP read your words just fine. They were wrong.
--

JR