Hi
I have an old telephone. Inside is a mobile phone. The handset is connect via a 3.5mm jack.
When I lift the receiver of the old telephone, I would like to send an on/off to the mic input which will let the cell phone know there is an off hook state.
When the handset is lifted, I have a terminal that is constantly open until the phone goes back on hook.
Q: How can I monitor that on hook/off hook status and when the circuit is open, send a short 500ms short to the mic input. I though maybe a 555 IC?
All help much appreciated.
Thanks
Simon
I have an old telephone. Inside is a mobile phone. The handset is connect via a 3.5mm jack.
When I lift the receiver of the old telephone, I would like to send an on/off to the mic input which will let the cell phone know there is an off hook state.
When the handset is lifted, I have a terminal that is constantly open until the phone goes back on hook.
Q: How can I monitor that on hook/off hook status and when the circuit is open, send a short 500ms short to the mic input. I though maybe a 555 IC?
All help much appreciated.
Thanks
Simon