Advanced Instruments 3900, User Manual

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The DB-9 RS-232 port on your instrument conforms to the DTE EIA-
232 standard and can reliably communicate over shielded cable up to 10
meters in length, depending on the baud rate you use. Almost every
item of information displayed by your instrument is also transmitted
over the RS-232 port, including test results, all error messages, and
most display data from the diagnostic menu.
Data is transmitted asynchronously as 1 start bit, 8 data bits and 1 stop
bit, with no parity. Each message transmitted from the communication
port is terminated by the sequence, Carriage Return (0D Hex), Line
Feed (0A Hex). Note that your instrument is only capable of outputting
information. At this time, there is no protocol for talking to the instru-
ment.
Sample RS-232 Setup
As a typical example of a communications program setup, the following
instructions will describe the process necessary for using your instru-
ment in conjunction with Hyperterminal for Windows
®
95 or later oper-
ating systems and a null modem cable, available from Advanced
Instruments, as shown in the diagram below. You can use this procedure
to be sure that your instrument and cable are operating correctly.
1. Create a Hyperterminal connection using the Hyperterminal pro-
gram.
2. While working within that connection, choose the Properties selec-
tion from the File menu.
101
Supplemental RS-232
Information
Appendix E