User's Manual

Telit GE863-GPS
Hardware User guide
1vv0300714, Rev. ISSUE#0, - 21/02/06
Reproduction forbidden without Telit Communication written authorization – All Right reserved – Right of modification reserved page 24 of 76
5 Serial Ports
The serial port on the Telit GE863-GPS is the core of the interface between the module and
OEM hardware.
4 serial ports are available on the module:
• MODEM SERIAL PORT
• MODEM SERIAL PORT 2 (GPS CONTROL PORT)
• GPS SERIAL PORT A (SIRF BINARY)
• GPS SERIAL PORT B (NMEA)
5.1 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-GPS 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-
GPS UART are the CMOS levels:
Absolute Maximum Ratings -Not Functional
Parameter Min Max
Input level on any
digital pad when on
-0.3V +3.75V
Input voltage on
analog pads when on
-0.3V +3.0 V