Terminal Processing 13
Echoing
Echoing
When echoing is enabled, Model 204 displays each input line on the user’s
output device as it is entered. Three classes of input lines can be echoed:
• Direct input to Model 204, either from the user’s terminal or from an
included procedure (see “Examples using LECHO and CECHO” on
page 15).
• Lines in which the FLUSH and ERASE editing characters were used (see
“Examples using LEECHO and CEECHO” on page 16). The line is echoed
as it appears after line-editing.
• Lines that contain dummy strings. The line is echoed after the dummy string
substitution has been made (see “Echoing parameters” on page 13).
A common example of echoing is the display of the input cards for a batch run
on the line printer. If echoing is in effect, input from a terminal is displayed on
the same terminal because it serves as both the input and the output device for
that user.
See “Echoing examples” on page 15 for examples of echoing.
Physical and logical line echo
Echoing can take place at two levels: physical line echo and logical line echo.
The Model 204 echo feature distinguishes between physical and logical input
lines. A physical line is a single line entered on the terminal. A logical line
consists of one or more physical lines of input.
Echoing can be specified at physical line level, logical line level, or both.
Normally only one class of echoing is specified. If both physical and logical line
echoing are enabled, the line is echoed twice.
If a physical line must be continued on another line, a nonblank character can
be inserted in the specified continuation column indicated by the INCCC
parameter. See “INMRL and INCCC parameters” on page 3 for more
information about the INCCC parameter.
Echoing parameters
The following parameters control echoing functions:
• CECHO controls the echoing of user and procedure input at the physical
line level.
• LECHO controls the echoing of user and procedure input at the logical line
level.
• CEECHO controls the echoing of physical lines that contain ERASE or
FLUSH characters.
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