O
[email protected]
- Jan 1, 1970
- 0
Hi,
I've been looking for a schematic of a telephone intercom that will use
a pair of phones, and deliver a proper ring voltage to the phone being
called (If I understand correctly, somewhere around 100V, 20Hz AC. I
would prefer if it also gives a dial/ring tone to the phone making the
call.
So far, what I've found are simple schematics that use a buzzer instead
of a ring signal, or line simulator schematics (such as this:
http://www.hotspot.freeserve.co.uk/HOTSPOT/TLS/tlsframe.htm ), which
seem to have too many features, and are too complex.
At the same time, I've found circuits to simply ring a phone, like this
pair (
http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#ring1.gif
).
Here are my questions:
1) Does anyone have a circuit that will already do what I am looking
for?
2) Could (and how would) I combine one of those ringer circuits with a
simple intercom circuit?
3) If I were to put the 20Hz AC signal into both the lifted and
unlifted phones at the same time, would it ring on the unlifted phone,
and give a dial tone on the other?
I should mention that I am trying to get this to work with 'old-style'
bell phones, so I would need to use a 20Hz signal, not 60 Hz, which I
have read works with new phones.
Thanks,
Ori
I've been looking for a schematic of a telephone intercom that will use
a pair of phones, and deliver a proper ring voltage to the phone being
called (If I understand correctly, somewhere around 100V, 20Hz AC. I
would prefer if it also gives a dial/ring tone to the phone making the
call.
So far, what I've found are simple schematics that use a buzzer instead
of a ring signal, or line simulator schematics (such as this:
http://www.hotspot.freeserve.co.uk/HOTSPOT/TLS/tlsframe.htm ), which
seem to have too many features, and are too complex.
At the same time, I've found circuits to simply ring a phone, like this
pair (
http://ourworld.compuserve.com/homepages/Bill_Bowden/page11.htm#ring1.gif
).
Here are my questions:
1) Does anyone have a circuit that will already do what I am looking
for?
2) Could (and how would) I combine one of those ringer circuits with a
simple intercom circuit?
3) If I were to put the 20Hz AC signal into both the lifted and
unlifted phones at the same time, would it ring on the unlifted phone,
and give a dial tone on the other?
I should mention that I am trying to get this to work with 'old-style'
bell phones, so I would need to use a 20Hz signal, not 60 Hz, which I
have read works with new phones.
Thanks,
Ori