Envoy Application Programming Manual
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Application Programming With Envoy
- 7 ADM-2 Multipoint Supervisor Protocol
- 8 TINET Multipoint Supervisor Protocol
- 9 Burroughs Point-To-Point Protocol
- 10 Asynchronous Line Supervisor Protocol
- A ASCII Character Set
- B ASCII to EBCDIC Code Conversion
- C File-System Procedures
- D Statistics Messages
- E S-Series Changes to Envoy
- NonStop™ Himalaya S-Series Server Architecture
- G-Series Migration Considerations
- CBSENSEON and CFSENSEON Modifiers
- LEOTRESYN and NOLEOTRESYN Modifiers
- Treatment of Characters After the Termination Character
- Number of SYN Characters
- DTR Drop
- Reporting of Parity Error
- Half-Duplex Support for Asynchronous Lines
- Controller Replacement
- SYSGEN and COUP
- Unit Numbers
- FDX Line Changes
- No Support for Auto-Call Unit
- Glossary
- Index
BISYNC Multipoint Tributary Protocol
Envoy Application Programming Manual—427159-001
5-29
CONTROL Procedure (Send WACK)
CONTROL Procedure (Send WACK)
The WACK sequence is used following a READ to delay the acknowledgment to the
supervisor while maintaining the communications link. The application sends WACK by
calling the CONTROL procedure and specifying operation 14 (Example 5-11
).
CONTROL Procedure (Send TTD)
The TTD sequence is used when the application process is not ready to transmit data,
but does not want to relinquish the line. The application sends TTD by calling the
CONTROL procedure and specifying operation 16 (Example 5-12).
Line-Error Handling
The figures and error code descriptions in this subsection show Envoy line-error
handling by Envoy for BISYNC multipoint tributary protocol READ and WRITE
operations.
This subsection includes:
•
Initial READ Operation on page 5-29
•
Continuation READ Operation on page 5-31
Initial READ Operation
Figure 5-3 shows the action of the tributary station in response to line conditions on an
initial READ.
Example 5-11. CONTROL Procedure (Send WACK)
CALL CONTROL (fnum,14)
| WACK -->
|
(CONTROL completes) <-- ENQ
error = 0
line state = READ
Example 5-12. CONTROL Procedure (Send TTD)
CALL CONTROL (fnum,16)
| STX ENQ -->
|
(CONTROL completes) <-- NAK
error = 0
line state = WRITE