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The packet type is determined by the TYPE code in the header:
0000 NULL 1 slot No payload. Used for acknowledgements or flow control. 0001 POLL 1 slot No payload. Used by the master to poll slaves. Requires acknowledgement. 0010 FHS 1 slot Frequency Hopping Sequence. Contains address, clock, etc. information 0011 DM1 1 slot Data, Medium rate. An ACL packet, which can interrupt the regular flow of SCO data. 0101 HV1 1 slot High quality Voice (1/3 rate FEC) 10 data bytes transmitted every 2 slots (data rate = 64,000 bit/sec) 0110 HV2 1 slot High quality Voice (2/3 rate FEC) 20 data bytes transmitted every 4 slots (data rate = 64,000 bit/sec) 0111 HV3 1 slot High quality Voice (no error correction) 30 data bytes transmitted every 6 slots (data rate = 64,000 bit/sec) 1000 DV 1 slot Combined Data/Voice. Can be transmitted in place of an HV1 packet.
The DV packet payload contains:
No error correction: 10 voice data bytes. 2/3 rate FEC: 1 payload header byte (as for an ACL packet);
0...9 data bytes;
2 CRC bytes.