Quantum Instruments DLT 7000 - Manual (Page 102)

Messages
4-12 Quantum DLT 7000 Tape System
NOTE
The tape drive supports initiating synchronous transfer negotiations
with the host, but this feature is disabled by default. To enable it,
set the MODE SELECT VU ERROM parameter EnaInitSyncNeg.
Bit
Byte
7 6 5 4 3 2 1 0
0 Extended Message Identifier (01h)
(see Figure 4-1)
1 Length (03h)
2 Message Code (01h)
3 Transfer Period: Min. = 25 (19h) (equals 100 ns)
4 Transfer REQ/ACK Offset: Max. = 15
Figure 4–4 Synchronous Data Transfer Request Message - Data Format