User Guide

Remote Control User Guide for the MX / MBX / TLX1 / TLX2 Series Chapter 1: Introduction
Rev. E, May 5, 2022 Page 3
Connecting to the MX /MBX / TLX1 / TLX2 Instrument Using the RS-232 Port on the Controlling Computer
Figure 4 illustrates the physical connection when the RS-232 ports on the MX / MBX / TLX1 / TLX2 instrument
and the controlling computer are used. The details of the connection depend on the controlling computer’s RS-
232 port. When it is a:
9-pin DB9 male connector, an option is to use a female-to-female 9-pin “null modem” cable. National
Instruments
®
explains the difference between a standard and a null modem cable here:
http://digital.ni.com/public.nsf/allkb/1EE0DD8AF67922FA86256F720071DECF
25-pin DB25 male connector, a null modem cable that converts between 25 and 9 pins can be used.
In either case, if a null modem cable is not available, a null modem adapter could be used with a standard cable.
Figure 4 Connecting the Computer and MX / MBX / TLX1 / TLX2 Series Instrument via the RS-232
Ports
If the USB port on the controlling computer is used, a USB cable terminating in a USB to RS-232 adapter can be
used to allow connection to a null modem cable. When the connector on the adapter is a 9-pin DB9 male, and the
null model cable has two 9-pin female DB9 connectors, it is possible to use the adapter and null modem cable to
make a connection between the computer’s USB and the MX / MBX / TLX1 / TLX2 instrument’s RS-232 ports.
This is illustrated in Figure 5.
Figure 5 Connecting the USB Port on the Computer to the RS-232 Port on the Instrument
Please note that the USB port on the MX / MBX / TLX1 / TLX2 instrument should not be connected to the RS-232
port on the controlling computer; this configuration is not supported.
Computer
RS-232
Port
USB
Port
Null Modem Cable
RS-232 Port
Null Modem
Cable
USB Cable
Computer
RS-232
Port
USB
Port
RS-232 Port
USB to
RS-232
Adapter