Old telephone to cell phone switch

[Simon Goddard]

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

 

[George]

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

Where is the cell phone in relation to the old phone, in the same room? How is the old phone connected to the cell? Is that the 3.5mm jack. I am just a little confused on your setup. If you could add a drawing showing what you have and how it is connected now if that is the case. Maybe add another drawing of what you want to happen. Some more information is needed.

You want to monitor the on/off hook status of the old phone when the circuit is open, what circuit? What do you want to send to the mic and is this mic the cell phone? If we are talking about sending a signal to the cell phone mic what kind of signal are you talking about? What will the cell phone do when it receives this signal? Will it call you on another line or something to that effect?

If you just want an indication of when the old phone receiver is off the hook that should be easy enough but the cell phone part has me confused (very easy to do lol).

George