6
Connector Definitions
6 Connector Definitions
All the VScom USB-COM devices provide the today standard DB9 male connector for the signals
of the serial ports. Some models may offer a DB25 male connector for RS232, other may provide
an additional Terminal block for RS422 and RS485 signals.
The signal assignment for RS232 on DB9 male connectors is defined by the term “RS232” already.
The same is for the DB25 male connector. Below is the signal definition for all connectors used by
the USB-COMs.
6.1 DB9 male
Usually this type of connector is used by customers. “4w” denotes the Full-Duplex mode, usually
named “4-wire”. Similarly “2w” denotes the Half-Duplex modes.
Pin
RS232
RS422
RS485 “4w”
RS485 “2w”
1
DCD
Tx
−
Tx
−
Data
−
2
RxD
Tx+
Tx+
Data+
3
TxD
Rx+
Rx+
4
DTR
Rx
−
Rx
−
5
GND
GND
GND
GND
6
DSR
RTS
−
7
RTS
RTS+
8
CTS
CTS+
9
RI
CTS
−
Table 7: DB9 male Connector
Figure 26: DB9 male Connector
June 2009
USB-COM PRO User Manual
30
