[McHUG] Phone Detection

[Charles Coffee]

Telephone circuits from MaBell are DC -48V, wont hurt a bit, however the 
ring is another story,
That can run up around 90 - 120V @ 16 to 20 cycles and will definitely 
give one a cheap thrill
(once had a tech that tested phone lines with his tongue until he was 
hit with the ring voltage - kinda
stopped that practice).

Use an opto and keep the phone line separated from your circuit, least 
you run afoul of Verizon
or your local carrier.  Old DAA would be great if you could find one, 
should run all of about
a buck to buy if they can still be found.

Chuck, KJ4GU