User's Manual

DE910 Series Hardware User Guide
1vv0300951 Rev.9 – 2015-05-11
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 46 of 77
8. Serial Port
The serial ports on the Telit DE910 are the interface between the module and OEM hardware.
2 serial ports are available on the module:
 Modem Serial Port 1 (Main)
 Modem Serial Port 2 (Auxiliary)
Several configurations can be designed for the serial port on the OEM hardware.
The most common are:
 RS232 PC comport
 Microcontroller UART@1.8V(Universal Asynchronous Receiver Transmit)
 Microcontroller UART@5V or other voltages different from 1.8V
Depending on the type of serial port on the OEM hardware, a level translator circuit may be
needed to make the system work.
Serial port 1 is a +1.8V UART with all the 7 RS232 signals.
Serial port 2 is a +1.8V Auxiliary UART.
The electrical characteristics of the serial port are explained in the following tables:
Absolute Maximum Ratings -Not Functional
Parameter Min Max
Input level on non-power pin with respect to ground
-0.3 +2.3V
Operating Range - Interface levels
Parameter Min Max
Input high level
1.5V 2.1 V
Input low level
-0.3V 0.35V
Output high level
1.35V 1.8V
Output low level
0V 0.45V