Honeywell HPB User Manual page 33

T
Computer
or Host
Processor
R
(1) See Table 4 for types of sequential response commands.
– Indicates there is no reply for this timing location
HPB HPB
CMD
ID=01 ID=02
Group=90 Group=92
A B C D
HPB
ID=03
Group=91
T - Transmit
R - Receive