OSR
= switch Data Set Ready
CO
= switch Carrier Detect
CTS=switch Clear To Send
RI
= switch Ring Indicator
switch is either YES or
NO.
You cannot abbreviate any of the
RS-232C line parameters.
As
specified
by
standard RS-232C conventions, a TRUE condition
means a logical
0,
or positive voltage. A FALSE condition means a
logical
1,
or negative voltage.
OTR
and RTS can
be
set to a constant TRUE by specifying the YES
switch. If
OSR,
CD,
CTS, or
RI
is
specified YES, the driver observes
that signal and waits for a TRUE condition before sending each
character.
If
specified
NO,
the driver waits for a false condition before
sending a character.
If
not specified, that signal is ignored.
The BREAK parameter allows you to set a logical BREAK character.
This is useful
in
"host" type applications. The BREAK parameter
causes the serial driver to set the system break bit whenever a
modem break (extended null) or
an
ASCII logical BREAK is received.
The system pause bit
is
set whenever the hex code 60 is received.
The system enter bit
is
set whenever a carriage return (00) is
received.
The default for BREAK is
3,
so a
(CONTROL1©
sets the break bit. Use
BREAK
= value to to set another character
as
the logical break.
Technical Examples
SETCOM
(BREAK)
(ENTER)
configures the RS-232C port to the default values. Specifying BREAK
with
no
value assigns the default value of 3 as the logical break
value.
SETCOM
(CTS)
(ENTER)
configures the RS-232C port to the default values. Because CTS is
specified, the driver looks at the CTS line for a TRUE condition before
it sends a character.
Sample Use
Suppose you want to log-on to CompuServe. First, you have to SET
*CL
to COM/OVR,
and
then you have to use SETCOM to set the
parameters of the RS-232C port
so
that your Model 4 can
communicate with CompuServe. See the Logging-On to CompuServe
section
in
the COMM utility description.
1-115
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