Serial (RS232) modem cable (DB25-DB25). Pinout and signals for building a serial (RS232) modem cable

This cable should be used for DTE to DCE (for instance computer to modem) connections with hardware handshaking.

D25 pin D-SUB female to the PC
DB25 pin D-SUB female to the PC
DB25 pin D-SUB male to the modem
DB25 pin D-SUB male to the modem

  Female Male Direction
Shield Ground
1
1
Transmit Data
2
2
—»
Receive Data
3
3
«—
Request to Send
4
4
—»
Clear to Send
5
5
«—
Data Set Ready
6
6
«—
System Ground
7
7
Carrier Detect
8
8
«—
Data Terminal Ready
20
20
—»
Ring Indicator
22
22
«—