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Signal & protocol details

Spectrum · audio inactive

02.5 kHz5 kHz7.5 kHz10 kHz

Microphone: Not opened
Input level: —
Link: —
Packets: —
Screen lock: Inactive
Recording

Protocol v8

One-way broadcast without acknowledgements. Coherent OFDM at 48 kHz: up to 320 carriers from 0.94 to 8.4 kHz (every 8th a pilot), 42.7 ms symbols plus an echo guard, QPSK or 16-QAM. Fast uses 16-QAM with a long echo guard and 398-byte packets for a nearby device in a normal room; Low Band stays below 3 kHz for weak speakers; Echo Guard uses a 20 ms guard for reverberant rooms. Long Range puts all power into 1.0–3.3 kHz with a low code rate for distant receivers. 5G NR LDPC codes with soft decoding; each packet carries 180 bytes (Fast: 398) and a CRC-16.

Files use a fountain code: any K packets rebuild K, in any order, so Send again or Repeat ×3 add new packets instead of copies. Short messages are one codeword; every repeat adds new parity. A sync burst (chirp, two training symbols, descriptor) starts every ~3.5 s, so receivers can join late.

Mode	Band	Guard	Modulation	Code rate	Speed	Needs