Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

62 Chapter3
Common Device Control Functions
Reading From Asynchronous Devices
alternative end-of-record character will be received, or that a
specified number of bytes will be received. It is implemented in
FDEVICECONTROL 192, parm1 = 65.
• Multiple alternative end-of-record (AEOR) characters. Allows an
application or user to specify up to 16 AEOR characters. When the
DTC receives one of these characters, it completes the current
pending read request with the received AEOR character as the last
byte of data. This functionality is implemented in
FDEVICECONTROL 192, parm1 = 66.
It is also implemented in TTUTIL.PUB.SYS, in the Special
Characters Screen. Refer to the Customizing Terminal and Printer
Type Files Using the Workstation Configurator manual for more
information on TTUTIL.
• Delete to backspace mapping. Allows the delete character (the
[DEL]
key) to be processed as a backspace character, in order to support
ANSI mode terminals. These terminals send the delete character
when the backspace key is pressed. This is implemented in
FDEVICECONTROL 192, parm1 = 67.
• Escape sequence read termination. Enables an application to have a
read terminated by an ESC sequence and receive the entire ESC
sequence in the data. It is implemented in
FDEVICECONTROL 192, parm1 = 68. An application cannot
enable both the escape sequence read termination and the inter-byte
timer method.
• Suppress echo of read termination character. Allows applications to
determine whether or not to include the read terminators with the
data that is echoed back to the device. It is implemented in
FDEVICECONTROL 192, parm1 = 69.
Refer to FDEVICECONTROL in Chapter 8, “Intrinsics Reference,” for
more information on these functionalities.
Data Editing Modes
When data is entered from a terminal, a number of control characters,
referred to as special characters, signal the DTC or the ASC software to
perform specific functions. The functions vary from deleting a character
from the input stream to interrupting a program or subsystem. All
special characters are stripped from the data after the system (or the
DTC) responds to them. The specific characters that will be treated as
special characters vary depending on the data editing mode being
employed. Standard editing, transparent editing, and binary editing
modes are available.