Envoy Application Programming Manual

Asynchronous Line Supervisor Protocol
Envoy Application Programming Manual—427159-001
10-18
CONTROL 11 and CONTROL 17 (Set DTR)
The file-system errors for the WRITEREAD procedure are the same as the errors for the
READ and WRITE procedures.
CONTROL 11 and CONTROL 17 (Set DTR)
The CONTROL 11 and CONTROL 17 procedure calls both do the same thing: they set
the data terminal ready (DTR) signal to true and wait for the data set ready (DSR) signal
from the modem or the network interface.
If you want these CONTROL operations to complete without waiting for DSR, you
must disable DSR detection in one of the following ways:
•
Issue CONTROL 17,0 to raise DTR without waiting for DSR.
•
Specify the DSRENSEOFF modifier when issuing the ADD DEVICE command.
•
Call the SETMODE 147 procedure.
SETMODE 147 parm1.<15> = 0 DSR detection enabled (default).
= 1 DSR detection disabled.
CONTROL 15 and SETMODE 15 (Break)
The CONTROL 15 procedure is used to set the transmission line to a break (or space)
condition.
The application must first invoke the SETMODE 15 procedure to define the following
output break characteristics:
•
Whether the break is noncontinuous or continuous.
•
Appropriate time interval for a noncontinuous break.
•
Break detect disable.
Example 10-3. WRITEREAD Procedure
Application Process Asynchronous Terminal
CALL WRITEREAD(message...)
|
| Transmit enabled and initiated
| on line.
| (message...) -->
|
(WRITE completes)
|
| Line now set to receive.
|
| <-- message
(READ completes)
error = 0
MCW.<8:15> contains message block number for this line