sndsend

Move short text between nearby computers through speakers and microphones using audible 4-FSK tones.

Idle

Send

0 bytes

Receive

microphone off
Rawrms 0.0000 / peak 0.0000
Buffer0.0 s
Settingsmic off
Syncwaiting
1200 Hz
0%
1600 Hz
0%
2000 Hz
0%
2400 Hz
0%
4 tones1200, 1600, 2000, and 2400 Hz carry two bits per symbol.
Frame syncPreamble and sync symbols let the receiver align to tone boundaries.
Compact textCommon text packs into 6 bits/char; anything else falls back to UTF-8, so Unicode still works.
CRC-16Corrupt transmissions are rejected instead of shown as bad text.