User`s guide

Terminal Types
In order for V+ to echo input characters properly and to generate certain displays on
character-based terminals, the type of terminal being used must be specified to the system.
The default terminal type (which is recorded on the V+ system disk) is assumed each time
the V+ system is booted from disk.
1
After the system is booted, the TERMINAL system
parameter can be set to specify a different terminal type.
Input Processing
Terminal input is buffered by the system but is not echoed until it is actually read by the V+
monitor or by a program. A maximum of 80 characters can be received before V+ begins to
reject input. When input is being rejected, V+ beeps the terminal for each character rejected.
On input, V+ may intercept special characters Ctrl+O, Ctrl+Q, and Ctrl+S, and use them to
control terminal output.
2
They cannot be input even by the GETC function. Their functions
are shown in the following table.
Char. Decimal Function
Ctrl+O 15 Suppress or stop suppressing output
Ctrl+Q 17 Resume output suspended by Ctrl+S
Ctrl+S 19 Immediately suspend terminal output
Special Character Codes
When Ctrl+O is used to suppress output, all output instructions behave normally, except that
no output is sent to the terminal. Output suppression is canceled by typing a second Ctrl+O,
by V+ writing a system error message, or by a terminal read request.
Other special characters are recognized by the terminal input handler when processing a
PROMPT or READ instruction, or when reading a monitor command. However, these
characters can be read by the GETC function, in which case their normal action is suppressed.
Char. Decimal Name Action
Ctrl+C 03 Abort the current monitor
command
Ctrl+H
08
Backspace Delete the previous input
character
Special Character Codes Read by GETC
Terminal I/O
V+Language User's Guide, v17.0
Page 202