Perle Systems 5500152-23 manual Definitions of Signals and Direction, EIA-232, EIA-422, EIA-485

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.

UltraPort Serial Adaptors User Guide	Chapter 3 Cabling information
Definitions of Signals and Direction	Page 102