R
R.Wieser
Hello all,
I'm in the need to detect a phone-lines status, and the specs tell me that
I'm allowed to use the equivalent of a 80 KOhm resistor. In that case I
expect (hope) that the voltage of the line will stay at least 30 Volts,
which than results in a current of just 0.375 mili-amps.
Now the fun part : I need to detect the status while my electronics are not
DC-coupled to the phone-line (the lines should be able to float, while my
electronics should be able to connect to a computer, which will pull it to
ground-level (or close to it) ).
I thought about using an Opto-coupler. The problem is that I've only used
opto-couplers that use, in comparision with the above, massive ammounts of
current (5-30 mA). As I'm entering unknown territory I could use some
advice ....
A allso won't say "no" to a pointer to an allready existing design
Suggestions to do it another way are welcomed allso.
Regards,
Rudy Wieser
I'm in the need to detect a phone-lines status, and the specs tell me that
I'm allowed to use the equivalent of a 80 KOhm resistor. In that case I
expect (hope) that the voltage of the line will stay at least 30 Volts,
which than results in a current of just 0.375 mili-amps.
Now the fun part : I need to detect the status while my electronics are not
DC-coupled to the phone-line (the lines should be able to float, while my
electronics should be able to connect to a computer, which will pull it to
ground-level (or close to it) ).
I thought about using an Opto-coupler. The problem is that I've only used
opto-couplers that use, in comparision with the above, massive ammounts of
current (5-30 mA). As I'm entering unknown territory I could use some
advice ....
A allso won't say "no" to a pointer to an allready existing design
Suggestions to do it another way are welcomed allso.
Regards,
Rudy Wieser