Envoy Application Programming Manual

Burroughs Point-To-Point Protocol
Envoy Application Programming Manual—427159-001
9-15
CONTROL Procedure (Send EOT)
CONTROL Procedure (Send EOT)
Sending an EOT returns the line to the CONTROL state. This control sequence should
be sent for the following purposes:
•
To give up master status after one or more WRITEs (alternatively, a turnaround
READ may be used for this purpose)
•
To reset the line when it is put into use
•
To reset the line after any error other than a normal error (0, 163, 165, 166, 167, 168,
or 171)
The application sends the EOT sequence by calling the CONTROL procedure and
specifying operation 13 (Example 9-6
).
CONTROL Procedure (Enable RVI)
When the local station is in the READ state and wishes to transmit a data block, it sends
a reverse interrupt (RVI) code as a positive acknowledgment instead of the normal ACK.
To enable RVI, the application uses the CONTROL 15 call prior to a continuation
READ (Example 9-7
). In response to CONTROL 15, Envoy sends an RVI at the start of
the next continuation READ. This RVI is a positive acknowledgment to the previously
received message.
173 Transmission error. Text was received with a character-parity
error or a block check character error. A NAK was sent, and
the message was retransmitted the number of times specified
by the retry value.
CONTROL
177 Text overrun. Either the data received while waiting for a line
bid exceeds three characters, or the message received exceeds
the length specified in the read count parameter. The READ
was attempted the number of times specified by the retry
value.
CONTROL
Example 9-6. CONTROL Procedure (Send EOT)
Local Remote
line state = any
CALL CONTROL(fnum,13)
| EOT -->
(CONTROL completes)
error = 0
line state = CONTROL
Table 9-12. Continuation WRITE File-System Errors (page 2 of 2)
Error
Number Description
Resultant
Line State