Re: Phone installation gurus
If you measure the DC voltage across the tip and ring (green and red wires) , you should read about 50 VDC. When you pick up any receiver, that voltage should drop to approx. 5 VDC. FYI, the phone co. rings your phones with approx. 90 Volts A/C at 20 cycles. Don't be holding a live pair when someone calls in....it'll wipe the smile off your face....
Disconnect the house side of your phones at the Demarc (outside box). Unplug all phones. Get a resistance reading of the green and red posts inside the Demark,this should show an open circuit, no resistance , you're reading the wires going to your phone blocks. If you find a high resistance across the pair, check for bad splices, shorts at the phone blocks. Look for shorts from staples etc. At the Demark, measure resistance again, this time, measure each leg (red-green) to the ground terminal. You should show an open circuit to ground on each leg. If you show resistance, one leg is shorted to ground , clear the short.
After the lines check good, reconnect the phones , one at a time, and test for proper ringing.
If you rewire a phone block and can receive calls, but can't make calls on the phone, you've reversed the pair at the block,just flip them over. This assumming you have DTMF (touch tone phones), rotary phones should be ok either way.
3 pair phone line (typically Cat3) is:
Blue/Blue white
Orange/Orange white
Green/Green white
Each pair is twisted on it's axis to reduce crosstalk.
In your wiring scheme, :
Red/Green = line 1
Black/Yellow = line 2
White/Blue = line 3
If your meter shows an open, that's good
