User's Manual

GE865 Hardware User Guide
1vv0300799 Rev.6 - 04/06/09
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 35 of 58
8.3 5V UART level translation
If the OEM application uses a microcontroller with a serial port (UART) that works at a voltage different
from 2.8 - 3V, then a circuitry has to be provided to adapt the different levels of the two set of signals.
As for the RS232 translation there are a multitude of single chip translators. For example a possible
translator circuit for a 5V TRANSMITTER/RECEIVER can be:
TIP: Note that the TC7SZ07AE has open drain output, therefore the resistor R2 is mandatory.
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