TIWAY I Network Communication
3-8
S5 UniLink Adapter Installation and Operation
3.4 TIWAY I HDLC Network Protocol
The TIWAY I network uses the HDLC protocol in the unbalanced, normal
response mode (UNRM) for transmission of commands and responses. In
this mode, a single Network Manager (primary) controls the flow of
messages between secondary devices.
Information flows between the primary and secondaries inside HDLC
I-Frames or information frames. The destination of the frame is specified by
the address field, the nature of the frame by the control field, and any data
specified by the information field. The TIWAY I primitive requests and
responses are encapsulated inside HDLC I-Frames according to the format
shown in Figure 3-6.
Flag Address Control Information FCS Flag
Primitives
Figure 3-6 HDLC Information Frame