How to make a radio call for an intercom handset?

Question

Electronics

You need a small device that you can put in your pocket and that will ring along with the intercom. What can be assembled from or maybe someone knows the finished product?

Answer 1

There is an LED (usually) - connect the LED of the optocoupler in series to it and then the optocoupler to the button on which thread the radio call is. The LED lights up - the radio call button is pressed and it rings somewhere in the pocket.

Answer 2

Take a regular wired phone that can dial a specific number at the touch of a button.
Program it to dial your phone number.
Next, you make a primitive delay line and a timer, put 2 relays. One picks up the phone, the other presses the button. Wait a few seconds, hang up. All.
You have your cell phone in your pocket. By a short call, you can guess that it was an intercom.
You can collect all this both from shit and sticks, and on all kinds of arduins with a GSM modem, if there is no wired phone.