NL865H2 Hardware Design Guide
1VV0301616 Rev. 7
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37
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2020-04-20
5.2.1.3.
RS232 LEVEL TRANSLATION
In order to interface the module with a PC com port or a RS232 (EIA/TIA-232) application
a level translator is required. This level translator must:
•
invert the electrical signal in both directions;
•
change the level from 0/1.8V to +15/-15V .
The simplest way to translate the levels and invert the signal is by using a single chip level
translator. There are a multitude of them, differing in the number of drivers and receivers
and in the levels (be sure to get a true RS232 level translator not a RS485 or other
standards).
An example of level translation circuitry of this kind is:
The example is done with a MAXIM MAX3238 Transceiver that could accept supply
voltages of 3.3V DC.
