Dave Smith Instruments TETRA - Manual (Page 73)

67
Mode Change: Combo Mode
Status Description
1111 0000 System Exclusive (SysEx)
0000 0001 DSI ID
0010 0110 Tetra ID
0011 0001 Select Combo Mode
1111 0111 End of Exclusive (EOX)
Packed Data Format
Data is packed in 8 byte “packets”, with the MS bit stripped from 7 parameter
bytes, and packed into an eighth byte, which is sent at the start of the 8 byte
packet.
Example:
Input Data
Packed MIDI data
1 A7 A6 A5 A4 A3 A2 A1 A0
1 00 G7 F7 E7 D7 C7 B7 A7
2 B7 B6 B5 B4 B3 B2 B1 B0 2 00 A6 A5 A4 A3 A2 A1 A0
3 C7 C6 C5 C4 C3 C2 C1 C0 3 00 B6 B5 B4 B3 B2 B1 B0
4 D7 D6 D5 D4 D3 D2 D1 D0 4 00 C6 C5 C4 C3 C2 C1 C0
5 E7 E6 E5 E4 E3 E2 E1 E0 5 00 D6 D5 D4 D3 D2 D1 D0
6 F7 F6 F5 F4 F3 F2 F1 F0 6 00 E6 E5 E4 E3 E2 E1 E0
7 G7 G6 G5 G4 G3 G2 G1 G0 7 00 F6 F5 F4 F3 F2 F1 F0
8 00 G6 G5 G4 G3 G2 G1 G0
This explains why it takes 293 MIDI bytes to transmit 256 Program data bytes.