Rocket 204 - IBM 3767 and NTO Terminals (IODEV = 37); Input Lines; Pausing and Canceling Output

40 Rocket Model 204 Terminal User’s Guide
IBM 3767 and NTO terminals (IODEV = 37)
IBM 3767 and NTO terminals (IODEV = 37)
This section summarizes the information needed to use IBM 3767s and the
terminals supported by NTO through SNA Communications Server.
Input lines
When Model 204 is ready to accept input, it issues the prompt character and
unlocks the keyboard. For 3767s supported by NTO, the prompt is the
underscore character (_), which is backspaced over immediately after it is
printed. For Teletypes supported by NTO, the prompt is the question mark (?).
Once the keyboard is unlocked, the user can enter a single input line, which
cannot exceed the number of characters specified in the INMRL parameter.
Therefore, Model 204 treats the following as end-of-message characters:
Pausing and canceling output
The system pauses at the end of each page of output if:
• OUTLPP (lines per page) parameter is positive.
• HDRCTL (header control) parameter has been set to 4.
Pausing at the bottom of the page allows the user to change the terminal paper
or to cancel the current request, if too much output is being received. The
system unlocks the keyboard at the bottom of each page to allow the user to
enter a response. The user causes continuation of output by entering a null line
(Return) or by entering any character.
If the user is receiving too much output, the attention key (BREAK or ATTN) can
be pressed at any time. Unless an ON ATTENTION statement is in effect (see
“Attention interrupt feature” on page 11), this cancels all output and aborts the
currently running request. If a procedure is being executed at the time of the
attention interrupt, all the input lines in the procedure are flushed, and the user
is returned to command level. The terminal keyboard is then unlocked, and the
terminal immediately signals that it is ready for input again.
Pressing the attention key while Model 204 is waiting for input causes the
system to respond with an error message, after which it immediately prompts
for input.
NL, FF For 3767 terminals
CR, LF, XON, XOFF For Teletypes and Teletype-compatible terminals