Rainbow Electronics GT864-PY - Manual (Page 16)

GT864-QUAD/PY Hardware User Guide
1vv0300756 Rev.0 08/ 05/07
Reproduction forbidden w ithout Telit Communications S.p.A. w ritten authorization - All Rights Reserved page 16 of 23
6 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 Terminal with all its functions. Through the
RS232 interface it can be used as GSM/GPRS modem for sending and receiving of SMS, Data and
Fax calls.
The
Telit GT864-PY , on the basis of the EASY SCRIPT® feature and with a PYTHON script
developed by the user, can allow self-controlled operations which put the RS232 interface in a
different serial data transmission mode, e.g. to communicate with a sensor or actuator.
6.1.1 RS232 standard interface connector
Connector type on the terminal is:
•
standard RS232 Sub-D 9pin female
•
Baud rate from 300 to 115.200 bit/s
•
Autobauding (300 to 38.400 bit/s)
The electrical characteristics of the serial port signals are shown below:
PIN Signal Direction Voltage levels Description
1 DCD Output
> + 4V
<- 4 V
Data carrier detect
2 RD Output
> + 4V
<- 4 V
Received data
3 TD Input
> + 2V
< 0.8 V
Transmitted data
4 DTR Input
> + 2V
< 0.8 V
Data terminal ready
5 GND - 0 V Ground connection
6 DSR Output
> + 4V
<- 4 V
Data set ready
7 RTS Input
> + 2V
< 0.8 V
Request to send
8 CTS Output
> + 4V
<- 4 V
Clear to send
9 RI Output
> + 4V
<- 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.