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Telephone central office question?

I was visiting a friend who had two out of three lines he had withdrawn from service. No one visited his home in order to stop the service. We measured the open circuit voltage across the lines. They were about 50V. The short circuit current was about 50mA. This matches what would be expected from a #26 twisted pair at the distance we were from the central office.

When service is suspended, what do telephone companies usually do at the central office?

We also measured the voltage of the remaining line with the telephones on hook. That was at about 30V. Moreover, it varied widely as we waited.

Does the typical telephone company now use subscriber line integrated circuits? What else could be happening?

Any links or references that cover modern day plain old telephone service practices would be appreciated.

Bill

-- Ferme le Bush

Reply to
Salmon Egg
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These days they just disable the line in the computer.

Reply to
gfretwell

In UK, BT just disable the line in software on the day service is suspended. Suspensions are often followed quickly by requests for reconnection (e.g. house or office changing hands), in which case it's a very cheap operation to re-enable the line (often for no charge). The longer the line remains out of service, the higher the likelyhood it will be disconnected from the line card in order to connect up another line.

Reply to
Andrew Gabriel

Does that mean that BT leaves the line permanently energized at about 50VDC? If so, that means that I can run a series string of LEDs and save on my lighting bill. :=)

Bill

-- Ferme le Bush

Reply to
Salmon Egg

The telephone company suspends the service by remote means. The service is pulled or disabled in the 5E switch located at the central office. The battery voltage usually remains. Eventually this will be removed when the cable pair or port at the switch is utilized for other services.

Reply to
none

Your better off tapping into a trunk.

Reply to
Igor The Terrible

Typically the telephone companies nowadays in countries with modern telephone network just disable the line in software level at the telephone central (just configure the telephoen port in such way that it cannot communicate with rest of the telephone network) and leave the line wires connected to telephone cental (at is constatly sending power to line). The lines are ususally disconnected only when specifically needed (somethign else gets connected to line or the central is running out of free ports).

Reply to
Tomi Holger Engdahl

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