Ampro Corporation Littleboard 550 manual DCD4, DSR4, RXD4, RTS4, TXD4, CTS4, DTR4

Chapter 3 Hardware

Pin #	Pin #	Signal	Description
	DB9
11	1	DCD4*	Data Carrier Detect 4 – Indicates external serial communications device
	(COM4)		is detecting a carrier signal (i.e., a communication channel is currently
			open). In direct connect environments, this input will be driven by DTR4
			as part of the DTR/DSR handshake.
12	6	DSR4*	Data Set Ready 4 – Indicates external serial communications device is
			powered, initialized, and ready. Used as hardware handshake with DTR4
			for overall readiness to communicate.
13	2	RXD4	Receive Data 4 – Serial port 4 receive data in
		RX4-	RX4- – If in RS485 or RS422 mode, this pin is Receive Data 4 -.
14	7	RTS4*	Request To Send 4 – Indicates Serial port 4 is ready to transmit data.
			Used as hardware handshake with CTS4 for low level flow control.
		TX4+	TX4+ – If in RS485 or RS422 mode, this pin is Transmit Data 4 +.
15	3	TXD4	Transmit Data 4 – Serial port 4 transmit data out
		TX4-	TX4- – If in RS485 or RS422 mode, this pin is Transmit Data 4 -.
16	8	CTS4*	Clear To Send 4 – Indicates external serial communications device is
			ready to receive data. Used as hardware handshake with RTS4 for low
			level flow control.
		RX4+	RX4+ – If in RS485 or RS422 mode, this pin is Receive Data 4 +.
17	4	DTR4*	Data Terminal Ready 4 – Indicates Serial port 4 is powered, initialized,
			and ready. Used as hardware handshake with DSR4 for overall readiness
			to communicate.
18	9	NC	Not connected (Ring Indicator 4)
19	5	GND	Ground
20	NC	NC	Not connected

Notes: The shaded area denotes power or ground. Signals are listed in the following order: RS232 followed by RS485/RS422

46 Reference Manual LittleBoard 550