8 Digital Communications Interface

8.1 Overview

The communication feature allowsan external device, such as a computer, to
communicatewith the 1529 to obtain measurement data and control operating
conditions. Communication is accomplished by issuing commands to the 1529
through RS-232, IR, or IEEE-488 communication ports.

8.2 Communications

The thermometer readoutis equipped with an RS-232 serial interface, an infra-
red window,and optionally a GPIB port. The serial interface allows communi-
cationsup to distances of approximately 50 feet. The IR interface allows
communications up to distances of 1 foot.The serial interface, infrared win-
dow,and GPIB port allow the user to access the functions, parameters, and set-
tingsdiscussed in Section 7, Menu Functions.

8.2.1 Serial Wiring

The serialcommunica-
tions cable attaches to the
thermometerr eadout
through theDB-9 connec-
tor atthe back of the in-
strument.Figure 49 shows
the pin-outof thisconnec-
tor and suggested cable
wiring.This type of cable
is typically referred to as a
“nullmodem” cable. To
eliminate noise, the serial
cable should be shielded
with lowr esistance be-
tween the connector
(DB9) and the shield.
The serialperiod, baud
rate, linefeed, and echo
are programmable. Refer
to Section 7.5.1.1, Serial
Port, for instructionson
accessing and setting
these parameters.
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8 Digital Communications Interface
Overview
Figure49 Serial Cable Wiring