What is the proper Line Voltage

[ve3slw]

What should the voltage be in Ontario in the Bell system for Loop Start lines? Both on hook, off hook and ringing.

 

[mitch1099]

Well not just for Ontario, It's 48 to I seen as hight as 52 volts DC on hook, offhook I would think is about the same, ringing is 90 volts AC 20 cycle.

 

[ISDNman]

The voltage off-hook will vary widely. There is no spec for this, but there is a spec for off-hook loop current (open one sice of the line and place an ammeter in series with one side of the line and then go off hook). Loop current should be between 23 and 120 milliamps.

When the line is ringing the 90 VAC 20 Hz is superimposed on the 48 volts DC.

 

[johnpoole]

46 to 52 is normal for any dms switch, you may get more voltage drop, depending on distance from the office. the main thing to check is loop current, above 20 mill, off hook on a silent line.

john poole
bellsouth business
columbia,sc

 

[shipwright]

The 48v dc comes off the negative terminal in the CO.