Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 51)

Asynchronous Link Protocols
Chapter 4
4-8
Figure 4.4 shows Path 1 with unrelated parts of Figure 4.3 removed.
Paths 2, 3, and 4 could be similarly shown.
Figure 4.4
Path 1, Unrelated Parts of Figure 4.3 Removed
Transmitter
A
Receiver
B
M S
Path 1 Path 1
11558
The full-duplex protocol is symmetrical; that is, anything that can be said
about Transmitter A, Receiver B, and Paths 1 and 2 applies equally to
Transmitter B, Receiver A, and Paths 3 and 4. There are actually two
independent instances of the protocol operating simultaneously. For
simplicity the protocol will be defined on the subsystem that carries
messages from A to B, with reference to Figure 4.5.
Figure 4.5
Message Transmission from A to B
Transmitter
A
Receiver
B
S
M
M
S
Path 2 Path 1 Path 2 Path 1
11559
Path 1
Path 2