GT864-3G Terminal Product Description
80269ST10071a Rev.0 - 14/09/0
9
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved
page 15 of 41
2.7 Serial Ports
The RS232 standard interface serves to connect a PC, Data Terminal Equipment (DTE) or an
application, which acts as host controller of the GT864-3G Terminal with all its functions. Through
the RS232 interface it can be used as GSM/GPRS/UMTS modem for sending and receiving of
SMS, Data and Fax calls.
2.7.1 RS232 standard interface connector
Connector type on the terminal is:
•
standard RS232 Sub-D 9pin female
•
Maximum baud rate to communicate with the GT864-3G is 230,4 kbit/s
The electrical characteristics of the serial port signals are shown below:
PIN
Signal
Direction
Voltage levels
Description
1
DCD
Output
> + 4 V
< - 4 V
Data carrier detect
2
RD
Output
> + 4 V
< - 4 V
Received data
3
TD
Input
> + 2,4 V
< 0.8 V
Transmitted data
4
DTR
Input
> + 4 V
< 0.8 V
Data terminal ready
5
GND
-
0 V
Ground connection
6
DSR
Output
> + 4 V
< - 4 V
Data set ready
7
RTS
Input
> + 2,4 V
< 0.8 V
Request to send
8
CTS
Output
> + 4 V
< - 4 V
Clear to send
9
RI
Output
> + 4 V
< - 4 V
Ring indicator
To connect to a PC as DTE, a pin-to-pin, 9 pin cable with D9 type connectors on both sides is
needed (1 male & 1 female). Shielding of this cable is recommended and its length shall not
exceed 3m.
