UltraPort Serial Adaptors User Guide
Definitions of Signals and Direction
Page 102
Chapter 3 Cabling information
Definitions of Signals and Direction
EIA-232
EIA-422
EIA-485
Direction
Description
RI
In
Ring Indicator
DCD
In
Data Carrier Detect
RTS
Out
Request To Send
RTS+
Out
Request to Send
RTS-
Out
Request to Send
DSR
In
Data Set Ready
TXD
Out
Transmit Data
TXD+
Out
Transmit Data
TXD-
Out
Transmit Data
TXD-/RXD-
In/Out
Transmit/Receive Data
TXD+/RXD+
In/Out
Transmit/Receive Data
RXD
In
Receive Data
RXD+
RXD+
In
Receive Data
RXD-
RXD-
In
Receive Data
S-GND
S-GND
S-GND
Signal Ground
CTS
In
Clear to Send
CTS+
In
Clear to Send
CTS-
In
Clear to Send
DTR
Out
Data Terminal Ready
C-GND
C-GND
C-GND
Chassis Ground
Note
Only the UltraPort SI series of cards supports EIA-422 and EIA-485
interface modes.