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 Centralized Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
4-35
CONTROL Procedure (Send WACK)
CONTROL Procedure (Send WACK)
The WACK sequence is used following a READ to indicate a temporary not-ready
condition while maintaining the communications link. The applications sends WACK by
calling the CONTROL procedure and specifying operation 14 (Example 4-14
).
CONTROL Procedure (Enable RVI)
The supervisor uses the RVI sequence when receiving messages from certain
manufacturer's terminals (for example, IBM 3270). After receipt of a message ending
with ETX, RVI informs the tributary station to stop sending. Enable RVI sends an RVI
sequence to the tributary in lieu of the normal ACK0/ACK1 sequence when the next
READ is performed. Enable RVI is permitted only once while the supervisor is in the
READ state. The application sends RVI by calling the CONTROL procedure and
specifying operation 15 (Example 4-15
).
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 4-16).
Example 4-14. CONTROL Procedure (Send WACK)
CALL CONTROL (fnum,14)
| WACK -->
|
(CONTROL completes) <-- ENQ
error = 0
line state = READ
Example 4-15. CONTROL Procedure (Enable RVI)
CALL CONTROL (fnum,15)
CALL READ
| RVI -->
|
v
Example 4-16. CONTROL Procedure (Send TTD)
CALL CONTROL (fnum,16)
| STX ENQ -->
|
(CONTROL completes) <-- NAK
error = 0
line state = WRITE