"One end of the cable terminates with a RJ11 jack and the other end terminates in an RJ11 wallplate."

Do you mean to say that you're trying to find out how create the cable that goes between the fax machine itself and the wall jack?

or

Are you trying to plug a cable into an existing wall jack, run it to another location/room and wire that end to a new wall jack?

or

Something else

I "FEATURE 00"

The standard is white/blue on green of jack and blue/white to red. In reality you can use any pair or combination of colors to wire a RJ 11 c.

One end of the cable will plug into an existing (provided by the phone company) box - so I need to attach an RJ11 jack to it.
The other end needs to terminate in a wall mounted face plate - allowing a user to plug a fax machine into into it.
I've googled a lot - and believe I've got the end to the face plate done right -
blue/white -- green
blue -- red
orange/white -- black
orange -- yellow
But I assume I am doing something wrong on the other end when trying to put the jack on.
I can't get it to work.
I make RJ45 cables all the time - but this is the first time I've attempted an RJ11.

Analog phone uses a single pair and it's always the middle of the jack and/or plug.

Wire your wall plate in the standard maner (568B).  Crimp you're 4 pin jack on so that the Blue-White/blue pair is on the middle 2 pins of the 4. For a simple phone line, the rest of the wires are superfluous.

Simple analog phones don't even really care about polarity.  If you look at some of the phone cords you get with phones, some of them even flip the wiring.  (All you real phone folks - don't slap me. )

If you really want to do it correctly, see this diagram: http://www.lanshack.com/wire_phone_jack.aspx.  Your 4-pin end would be pins 2-5 in the diagram.

Jeff
It's never too early to begin preparing for International Talk Like a Pirate Day
"The software I buy sucks,  The software I write sucks.  It's time to give up and have a beer..." - Me

Oops, I looked at that again.  Wire your jack as the diagram shows as well rather than 568B.

Jeff
It's never too early to begin preparing for International Talk Like a Pirate Day
"The software I buy sucks,  The software I write sucks.  It's time to give up and have a beer..." - Me

Quote:

One end of the cable will plug into an existing (provided by the phone company) box - so I need to attach an RJ11 jack to it.

If the telephone company provided box has screw terminals, use the White/Blue and Blue/White wires on them (White/Blue on Green, and Blue/White on Red)

If the telephone company provided box has an RJ-11 jack on it, terminate your Cat-5 cable on another RJ-11 jack, using the White/Blue and Blue/White wires, then plug a standard telephone cord between the two.

Quote:

The other end needs to terminate in a wall mounted face plate - allowing a user to plug a fax machine into into it.

And here, just connect the White/Blue wire to the Red screw terminal, and the Blue/White wire to the Green terminal.