Sony Ericsson GM29 - Manual (Page 8)

8 Electrical Connections
RS232 Serial Port
The modem supports a standard RS232 serial
interface (EIA/TIA 574) via its 9 pin Sub-D
connector, shown below.
Link the GM29 to a microcontroller or
computer in the host application, via the RS232
serial port. AT commands are used by the
host-application software to communicate with
the GM29.
Sub-D 9-pin Connector
Signal Voltage
levels Description
DCD > +4 V
< –4 V Data carrier detect
RD > +4 V
< –4 V Received data
TD > 2V
< 0.8V Transmitted data
DTR > 2V
< 0.8V Data terminal ready
GND 0 V ground connection
DSR > +4 V
< –4 V Data set ready
RTS > 2V
< 0.8V Request to send
CTS > +4 V
< –4 V Clear to send
RI > +4 V
< –4 V Ring indicator
9
1 DCD
2 RD
3 TD
4 DTR
5 GND
6 DSR
7 RTS
8 CTS
9 RI
7 6
5 4 3 2 1
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