Phone voltage
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-48VDC is "nominal" voltage, just like 12 volts is nominal in a car (but is around 13.5 volts on charge).
For a phone line. you would typically see around -54 volts DC with the phone hung up.
If you really want to try something neat, put your fingers across the line and phone the phone number. Let me know what happens.
For a phone line. you would typically see around -54 volts DC with the phone hung up.
If you really want to try something neat, put your fingers across the line and phone the phone number. Let me know what happens.
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2,115 Posts
Normal voltage leaving the Central Office -48 to -52 VDC. The closer you are to the CO the higher the voltage. I had an office building that shared the same parking lot as the CO, the incoming dial tone was so hot I had to use resistors to knock it down so it would be compatible with their phone system.
I was taught red-right-ring-ridge.
Yep, rough or ridge..any tactile.
I am reading this thread and I could be reading another language. I never deal with phones anymore and when we do it is resi stuff.
I did get knocked on my butt under a commercial building when I ran into some phone wires hanging there -- I assumed there wasn't much voltage there--- surprise
I did get knocked on my butt under a commercial building when I ran into some phone wires hanging there -- I assumed there wasn't much voltage there--- surprise
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1,887 Posts
Hey Tywrapp you ever use the spit on finger method to test for polarity? Hurts like heck when you get across ring voltage and ground but it is a good trick!
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Ring side of the circuit...
Right side of the terminal block
Red conductor (this is on the old red, green, yellow, black quad wire. Doesn't apply to new Cat5)
Rough/Ridge. On the old parallel strand service wire, one side was smooth and the other side has a protruding ridge. ( The latest style of service wire is color coded like Cat5).
All of this is the positive (dial tone) side of the circuit. Keeps the polarity straight as you build the circuit.
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Never tried that! My way to rest for polarity was to take one lead from the head set to ground and the other lead to each conductor until I drew dial tone.
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2,115 Posts
Most likely a Special Circuit (T-1). 180 volts
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My new Greenlee buttset usually shows - 47 volts.
I have a trick for using a toner to locate a line in a sea of 66 blocks.
Install the tone generator on the line in question. Check for tone at the generator and on the phone line. If no tone, the line is shorted somewhere. If you have a good tone, go to the 66 blocks and start the search by pushing the switch on the receiver and while holding it down put your finger on the tone receiver's tip. With the other hand, use a finger to run the 66 blocks. This attenuates the signal down to a single pair. Instead of reading the tone everywhere, you have located your wires. To verify, use a jumper to short the pair, The tone will go away.
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Seriously?!?
Link?
:jester:running joke with B4T:jester:Seriously?!?
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