Telit Wireless Solutions GE863-QUAD Manual Do Utilizador

 
 
 
 

 

 

 1vv0300715 Rev. 1 - 19/09/06  

  

Reproduction forbidden without Telit Communications S.p.A. written authorization - All Right reserved 

 

page 24 of 79 

 

•  MODEM SERIAL PORT 
•  MODEM SERIAL PORT 2 (DEBUG) 
 

6.1 MODEM  SERIAL  PORT 

Several configurations can be designed for the serial port on the OEM hardware, but the most 
common are: 

•  RS232 PC com port 

•  microcontroller UART @ 2.8V - 3V  (Universal Asynchronous Receive Transmit)  

•  microcontroller UART@ 5V or other voltages different from 2.8V  

 
Depending from the type of serial port on the OEM hardware a level translator circuit may be needed 
to make the system work. The only configuration that doesn't need a level translation is the 2.8V 
UART. 
The serial port on the GE863-QUAD/PY is a +2.8V UART with all the 7 RS232 signals. It differs from 
the PC-RS232 in the signal polarity (RS232 is reversed) and levels. The levels for the GE863-
QUAD/PY UART are the CMOS levels: 
 
 

 

 

Input level on any 
digital pad when on 

-0.3V +3.75V 

Input voltage on 
analog pads when on

-0.3V +3.0 

V 

 

 

 

 

Input high level    V

IH 

2.1V 3.3V 

Input low level     V

IL

 0V 

0.5V 

Output high level V

OH

 2.2V 

3.0V 

Output low level  V

OL

 0V 

0.35V