Envoy Application Programming Manual

BISYNC Centralized Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
4-36
Line-Error Handling
Line-Error Handling
The figures and error code descriptions in this subsection show how Envoy handles line-
errors for BISYNC multipoint supervisor protocol READ and WRITE operations.
This subsection includes:
•
Initial READ Operation on page 4-36
•
Continuation READ Operation on page 4-39
•
Initial WRITE Operation on page 4-41
•
Continuation WRITE Operation on page 4-43
Initial READ Operation
Figure 4-6 shows the action of the supervisor station in response to line conditions on an
initial READ.
Note. A call to CONTROL 20 after a READ monitors the line for control characters without
sending an acknowledgment for the preceding message (received by the READ). File-system
errors are used to indicate what was received from the host.