User`s guide

4-6
Programming over RS-232-C
Configuring the Interface
The TD (Transmit Data) line from the oscilloscope must connect to the RD
(Receive Data) line on the controller. Likewise, the RD line from the
oscilloscope must connect to the TD line on the controller.
The RTS (Request To Send) line is an output from the oscilloscope which can
be used to control incoming data flow. A high on the RTS line allows the
controller to send data, and a low on this line signals a request for the controller
to disable data transmission.
The CTS (Clear To Send), DSR (Data Set Ready), and DCD (Data Carrier
Detect) lines are inputs to the oscilloscope which control data flow from the
oscilloscope (Pin 2). Internal pull-up resistors in the oscilloscope assure the
DCD and DSR lines remain high when they are not connected.
If DCD or DSR are connected to the controller, the controller must keep these
lines and the CTS line high to enable the oscilloscope to send data to the
controller. A low on any one of these lines will disable the oscilloscope data
transmission. Dropping the CTS line low during data transmission will stop
oscilloscope data transmission immediately. Dropping either the DSR or DCD
line low during data transmission will stop oscilloscope data transmission, but
as many as two additional bytes may be transmitted from the oscilloscope.
Configuring the Interface
Use the controller mode when you operate the instrument with a controller over
RS-232-C. To set up the RS-232-C interface on the oscilloscope, refer to the “To
set up the I/O port to use a controller” topic in the Utilities chapter of the User’s
Guide.
Make sure that the RS-232-C settings on your oscilloscope match the settings
of your COM1 or COM2 port on your pc.