USB-COMI PRO / USB-2COMI PRO USER’S MANUAL
14
5
SERIAL PORT CONNECTOR PINOUT
5.1
RS-232 Mode Pinout of 9-pin D-sub Connector
The RS-232 serial ports are configured as data terminal equipment (DTE), with a 9-pin
D-sub connector. Pin assignments are according to TIA/EIA-574, which formally defines
the assignments for a COM port that are found on many personal computers.
Pin Number Pin Type
Description
1
Input
DCD
Data Carrier Detect
2
Input
RxD
Receive Data
3
Output
TxD
Transmit Data
4
Output
DTR
Data Terminal Ready
5
Ground
GND
Signal Ground
6
Input
DSR
Data Set Ready
7
Output
RTS
Request to Send
8
Input
CTS
Clear to Send
9
Input
RI
Ring Indicator
RS-232 pinout for DB-9 connector
5.2
RS-232 Mode Pinout of 5-pin Terminal Block
Pin Number Pin Type
Description
1
Input
DCD
Data Carrier Detect
2
Input
RxD
Receive Data
3
Output
TxD
Transmit Data
4
Output
DTR
Data Terminal Ready
5
Ground
GND
Signal Ground
RS-232 pinout for 5-pin terminal block connector
