Ring--------------------
|
C
O = Transformer coupling coil at central office
I
L
| | -48V |
------||||----R------
| | | |
| C Filter
| |
|-------------R------
| |
GND C
O = transformercoupling coil at central office
I
L
|
Tip-------------------
Here is a two wire subscriber loop -oversimplified?
The R's in the line are typically 200 ohms
Larry Truthan
-----Original Message-----
From: Arfon Gryffydd [mailto:arfonrg_at_texas.net]
Sent: Wednesday, December 08, 1999 4:30 PM
To: Discussion re-collecting of classic computers
Subject: Re: Teleco Question... More on my devious plan....
Okay forgive my ignorance but....
Q1)Which way to power a telco line? (Note: subsitute "modem" for
"telephone")
A) Series?
--------Battery----------
| |
Telephone Telephone
|_________________________|
or
B) Shunt?
-------------------------
| | |
Telephone Battery Telephone
|____________|____________|
Shunt seems more correct but, I think the power source's filtering would
filter out the audio.
Q2)Which lead is NORMALLY the positive (red or green)?
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Received on Wed Dec 08 1999 - 16:18:21 GMT