Rs232/Rs485 Interfaces - East Tester ET51 Series User Manual

requirements for the interface, as this may cause damage to the interface
or even the instrument.
When connecting, ensure the connectors at both ends of the
communication cable are securely connected. Loose connections may
lead to communication failures or other accidents.
According to the RS-232C standard, if a MODEM is not used and
the symbol distortion remains below 4%, the maximum transmission
distance between data communication equipment and data terminals is
limited to 15m (50 feet). Therefore, when using RS232 communication,
please ensure that the connection length do not exceed 15m.

4.2 RS232/RS485 Interfaces

4.2.1 RS232 Interface
RS232C (RS stands for the recommended standard, 232 for the
standard number, and C for the version number) is a communication
protocol developed by American organizations such as the EIA and BELL
and published in 1969. In industrial control, it typically involves three
lines: RXD, TXD, and GND, akin to this product.
The wiring method for the instrument's RS232 interface is as shown
in the diagram below. When connecting, please use the applicable DB9
male connector. For this product, only pins 2, 3, and 5 are used.
Crossover wiring should be adopted between communication ends, with
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