Interfaces and Connectors
EPM-15 Reference Manual
35
Null Modem
The following diagram illustrates a typical DB9 to DB9 RS-232 null modem adapter.
System 1
<--> System 2
Name
Pin
Pin Name
------------------------------------
TX
3 <-->
2 RX
RX
2 <-->
3 TX
RTS
7 <-->
1 DCD
CTS 8
DSR
6 <-->
4 DTR
DCD
1 <-->
7 RTS
8
CTS
DTR
4 <-->
6 DSR
Pins 7 and 8 are shorted together on each connector. Unlisted pins have no connection.
