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
Full-Duplex Protocol
Envoy Application Programming Manual—427159-001
6-6
Message Formats
OPEN
Enables access to a communications line.
READ
Accepts incoming messages received from the remote station.
SETMODE
Alters the line characteristics (Table 6-2).
WRITE
Transmits data to the remote station.
Message Formats
The message formats used by the Envoy full-duplex protocol conform to the
corresponding heading and text formats defined by the IBM Binary Synchronous
Communications standard. Before sending a message, the application process must put
control characters in the message according to the message type. When the application
process receives a message, it removes these control characters. The full-duplex protocol
does not allow messages to contain SYN characters, block-check characters (BCC), or
inserted DLE characters for transparent text.
The Envoy full-duplex protocol defines message formats for normal text, transparent
text, and headings. All messages must end with either an ETX or an ETB control
character; other endings are invalid. A special interrupt handler discards improperly
formatted messages and messages with BCC errors.
Table 6-2. SETMODE Operations for Full-Duplex
Operation Parameter Description
15 1 Specifies timeout duration in 10 millisecond units.
16 1.<3> 0: Disables application’s ability to receive control charac-
ters.
1: Enables application to receive control characters.
18 1 Sets statistics threshold
Note. For a complete list of SETMODE procedures supported by the Envoy protocols, see the
SETMODE procedure description in Ta ble C-5
on page C-27, which also lists the analogous
modifier for these procedures.