🚀 go-pugleaf

Greetings,
 
I am installing the second phase of a house alarm system, and among other
things, I want to report on the failure of a phone line.  After looking up
the various voltages and polarities that exist depending on the status
of the phone (on hook, off hook, ringing, etc), it seems that the simplest
approach is to connect ring and tip to the to AC legs of a full wave
bridge rectifier, then series a resistor (say 1k) with a small capacitor
(say .5uf) across the DC legs, and monitor the voltage across the cap.
Oops, add a 10k resistor across the cap to drain the charge, but not enough
to load the phone line.  When it goes to zero, the phone company is no longer
on the other end of the line.
 
Obviously, I want the existing phones to continue working as before, and this
unit should not add any appreciable load to the phone line.
 
Am I missing something?  This seems simple enough to set up tonite.
Comments?  Thank you all - this list is an *excellent* technical reference!
                                - Frank
*************************************************************************
Frank Tompkins           º   Internet: X1FT@VM1.CC.UAKRON.EDU
University of Akron      º
Akron, Ohio   44325-3501 º
  "I have not failed, I've just found 10,000 ways that won't work"
                                                     - Thomas Edison