HP AD278A and AD279A PCI Multiplexer Support Guide, November 2008

Table B-8 Terminal/Printer Cable with RTS/CTS Handshaking
DB-25 Male (Peripheral)RJ-45 8-Pin Plug (MUX Port End)
SignalPinPinSignal
DTR20Connected to1DSR
CTS5Connected to2RTS
GND1 (or shell)Connected (via
shield) to
3GND
RxD3Connected to4TxD
TxD2Connected to5RxD
SG7Connected to6SG
RTS4Connected to7CTS
DCD8Connected to8DTR
IMPORTANT: Some terminal or printer manufacturers may use different methods of flow
control. Consult your documentation for specific wiring requirements.
RJ45 Fully-Wired Terminal/Printer Cable
Using a 10-pin RJ45 plug, the cable wiring shown in Table B-9 supports most serial terminals or
printers with either software of hardware handshaking. This cable is valid with any RJ-45 serial
port.
Most terminals and printers use Request to Send/Clear to send (RTS/CTS) for hardware
handshaking. The cable shown supports this method.
Table B-9 lists the pin-out connection between the RJ45 adapter and the DB25 terminal/printer
with RTS/CTS handshaking.
Table B-9 Terminal/Printer Cable for Software (XON/XOFF) or Hardware (RTS/CTS) Handshaking
DB-25 Male (Terminal/Printer)RJ-45 10-Pin Plug (MUX Port End)
SignalPinPinSignal
DTR20Connected to2+10DSR+DCD
CTS5Connected to3RTS
GNDShellConnected (via
shield) to
4GND
RxD3Connected to5TxD
TxD2Connected to6RxD
SG7Connected to7SG
RTS4Connected to8CTS
DSR+DCD6+8Connected to9DTR
IMPORTANT: Some terminal or printer manufacturers may use different methods of flow
control. Consult your documentation for specific wiring requirements.
RJ-45 10-Pin Plug to DB-25 Modem Cable
The simplest way to connect a modem to a RJ-45 jack is to use a RJ-45 to DB-25 cable adapter.
RS-232 Asynchronous: RJ-45 37