It's possible. Phone transducers can send/receive up to around 20kHz.

Most adult humans can't hear beyond about 15kHz.

You'd need to keep in mind transmission distance which decreases with frequency which can be either a feature or a bug.

You can apply the same principles as Satoshi Jump using DTMF + The Goertzel Algorithm for tone detection. DM one of us if you'd like to learn more.