Send data via GSM voice channel with uart

HI,

Is it possible to send a variable through the GSM microphone input via TX using UART and read data via speaker output by calling another phone?

No.

Grumpy_Mike:
No.

How the Crypto cell phones work. How to send analog digitized sound

How the Crypto cell phones work.

https://en.wikipedia.org/wiki/Crypto_phone

How to send analog digitized sound

https://www.electronicdesign.com/communications/understanding-modern-digital-modulation-techniques

Google not working where you live?