Telit Wireless Solutions GE863-QUAD - Manual (Page 28)

GE863-QUAD
GE863-PY
1vv0300715 Rev. 1 - 19/09/06
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved page 28 of 79
The RS232 serial port lines are usually connected to a DB9 connector with the following layout:
6.4 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, but since the
translation requires very few components, then also a discrete design can be suited. For example a
possible inexpensive translator circuit for a 5V driver can be: