On Jun 19, 1:27*pm, Cydrome Leader wrote:
wrote:
Telco keeps screwing up my phone line (ca every 18mo for the pst 10yrs) and
insists they need to come in because it's my fault. Usually they cut my line
while they are installing a neighbor's line. Most recently, it prolly was the
squirrels. So, instead of removing ten gadgets to prove it's their fault, I
want a one second op

I found the earliest undivided phone line netering my house and put a 2way
2pole switch on it so I can switch from the main ingoing line to an RJ11
jack.. *but I said, why should i need to hook up a phone to this to test the
line, why not an LED.. *Ok, it seems I need 2.7K resistor in series.. *seems
easy'nuff.. since it switches on only momentarily, I wonder if I'm
overkilling

So you're going to call the phone company and explain your line is bad and
you can prove it with a LED you wired into the line?

good luck with that.

And as soon as you tell them you did that they will have justification
to blame YOU for the whole damn thing, or whatever it is that you're
complaining about. You might even find a charge for a service call on
your bill as well.

If you understand anything about telephone equipment, your line sits
at 48VDC when the phone in on hook, (hung up). When it rings, an AC
voltage, usually at a frequency of 20HZ is superimposed on the line.
When you, your fax machine, or modem etc. "answers" the call your line
goes "off hook". During this condition a line "loop" current, usually
in the order of around 20ma. between your house and the central
office), commonly referred to as the CO is developed. The central
office equipment detects this current and removes the ringing voltage,
and a conversation is established between you and the caller. At this
point your line is sitting at about 6VDC until you hang up, whereupon
the line returns to 48VDC.

An LED, (along with the appropriate series resistor) will only draw a
few milliamps from a 48V line so I don't think that it would trigger
an off hook detection, however I really don't understand what it is
you are actually trying to accomplish.

If you need an indication of the 48V look at it with a meter or just
pick up the phone and listen for dial tone. If it's a visual
indication of ringing current you need I'm sure that you can find a
schematic on line to build one, or as previously mentioned you can
just use an NE2 neon bulb with a small resistor in series. This will
draw no current until the phone rings. There are also several
commercially made units available that will do this. I would start
with Radio Shack. They used to have these. I don't know if they still
do. Keep in mind though that if anything you hang on a phone line in
any way interferes with it, and it is determined that the device was
not FCC registered, ( or probably even if it was) the phone company
can come at you full bore. Lenny