Any telephone wiring experts out there?

I suspect that you have switched the wires you that you are looking at one wire from each pair.

I suggest to go back to the interface and "do it by the numbers:"

1. Put working telephones into each of the two jacks at the interface and ensure you have good dial tone(s) at the interface. (If not, it is a telco problem.)

2) Disconnect ALL wires from the terminals in the interface. 3) Connect one PAIR at a time and ensure that the telephone works at the other end. (Pair #1 is usually red/green, pair #2 is black/yellow) The terminal block is usually color coded.

Start with the assumption that you haven't "used proper wiring, etc." :-)

You might try posting to alt.dcom.telecom and comp.dcom.telecom.tech, but you'll need to provide some details about just exactly what you have and how you wired it. In fact, if you reply to this message, I'm setting Followup-to: header to those newsgroups and deleting alt.engineering.electrical.

First, describe the symptoms better. I have no idea what you mean by "I can hear both phone lines when..." Describe what you are doing and what you hear. Do you mean that when you pick the phone and push the button for Line 1 you are connected to both lines? Someone who picks up another extention on either line will be heard??? But when you push the button for Line 2 you hear nothing at all???

That sounds as if you've got the connections to the telco interface correct, because you can hear each of the two lines. But somewhere you've made it so that instead of connecting to the two lines on the telephone set, you've got the both connected only to Line 1 at the telset. What kind of a telephone set, and how are you connecting to it?

I don't know just how you might have done that, but I've seen people work at tying down cables for an hour before discovering they were off by one pin...

I hain't never ever done nothing like that myself, of course... ;-)

From the phone interface in the basement, I ran wire approx. 20 feet and up through the floor. At the phone jack in the wall, I just matched the four colors (red to red, green to green, etc.). I am using a RadioShack two-line caller ID phone with speakerphone (which worked fine previously). When I picked up line 1, I heard an echoing dial tone so I decided to check my voice mail to see if I could dial out. I was using speakerphone to dial and my passwords to access both lines are the same. Oddly enough, after entering my password, I heard messages I had saved from both lines at the exact same time. I figure the echoing sound I heard is dial tones from line one and two.

You should really be using twisted pair cable for RJ14 service (2 lines). That is typically blue/white, white blue for line 1 and orange white/white orange for line 2. You will hear crosstalk if the wires are straight through.