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Appendix B
Null Modem Cable
Specifications
The DB-9 cable is used for connecting a terminal or terminal emulator to the
Managed Switch’s RS-232 port to access the command-line interface.
The table below shows the pin assignments for the DB-9 cable.
Function Mnemonic Pin
Carrier CD 1
Receive Data RXD 2
Transmit Data TXD 3
Data Terminal Ready DTR 4
Signal Ground GND 5
Data Set Ready DSR 6
Request To Send RTS 7
Clear To Send CTS 8
9 Pin Null Modem Cable
CD 1 4 DTR
DSR 6 1 CD
DTR 4 6 DSR
RXD 2 3 TXD
TXD 3 2 RXD
GND 5 5 GND
RTS 7 8 CTS
CTS 8 7 RTS
Reserve 9 9 Reserve