User's Manual

CL865-DUAL Hardware User Guide
1vv0301104 Rev.1 – 2014-03-07
Reproduction forbidden without written authorization from Telit Communications S.p.A. - All Rights
Reserved. Page 38 of 70
Mod. 0805 2011-07 Rev.2
9. Serial Port
The serial ports on the Telit CL865 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.
On the CL865 the ports are CMOS 1.8V.
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 (1.8V CMOS)
Parameter
Min
Max
Input high level
1.5V
2.1 V
Input low level
0V
0.35V
Output high level
1.35V
1.8V
Output low level
0V
0.45V