RS-232 Cables and Connector Options
45
Connector Options
A variety of connector types is available. Four and eight-port boards can be set
up with DB-25 connectors (male or female, DTE or DCE wiring), DB-9
connectors (male or female, DTE wiring) or 10-pin RJ-45 jacks. Sixteen-port
boards are available only with DB-25 connectors (male, DTE wiring).
The following pages give the part numbers and wiring information for the
various connector types.
DB-25 Connectors
Table 5
DB-25 Connector Pin Assignments
Signal
Description
DTE Use
DCE Use
Pin #
GND
Chassis Ground
N/A
N/A
Shell
TxD
Transmitted Data
Output
Input
2
RxD
Received Data
Input
Output
3
RTS
Request to Send
Output
Input
4
CTS
Clear to Send
Input
Output
5
DSR
Data Set Ready
Input
Output
6
SG
Signal Ground
reference
reference
7
DCD
Data Carrier Detect
Input
Output
8
DTR
Data Terminal Ready
Output
Input
20
RI
Ring Indicator
Input
Output
22
DigiBoard four and eight-port boards can be configured with DB-25 connectors
in any of four configurations: DTE male, DTE female, DCE male or DCE
female. Sixteen-port boards are available only with the DTE male configuration.
The pin assignments for the DB-25 connectors follow the usual conventions for
RS-232 wiring.
It should be noted that the DCE configuration is equivalent to a DTE connector
plus a fully-wired null modem adapter. Thus, DCD (Data Carrier Detect) and
DSR (Data Set Ready) are wired together internally and carry the DTE
equivalent of DTR (Data Terminal Ready). For this reason, DCE cables cannot
be used with modems.
