GE864-QUAD V2 Hardware User Guide
1vv0300841 Rev.5
–
2017-05-11
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights
Reserved.
Page 43 of 77
9.
Serial Ports
The serial port on the Telit GE864-QUAD V2 is the core of the
interface between the module and OEM hardware.
2 serial ports are available on the module:
MODEM SERIAL PORT (Main, ASC0)
MODEM SERIAL PORT 2 (Auxiliary, ASC1)
9.1.
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 does not need a level
translation is the 2.8V UART.
The serial port on the GE864-QUAD V2 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 GE864-QUAD V2 UART are the CMOS levels:
Absolute Maximum Ratings
–
Not Functional
Parameter
Min
Max
Input level on
any digital pad
when on
-0.3V
+3.1V
Input voltage
on analog pads
when on
-0.3V
+3.0 V
Operating Range
–
Interface levels (2.8V CMOS)
Level
Min
Max
Input high level
V
IH
2.1V
3.1V
Input low level
0V
0.5V
