Standard Horizon GM29 manual RS232 Serial Port, Dcd, Dtr Gnd Dsr, Rts Cts

2. ELECTRICAL DESCRIPTION

2.5 RS232 Serial Port

The modem supports a standard RS232 serial interface (EIA/TIA 574) via its 9 pin Sub-D connector, shown below. In line with serial communication terminology the GM29 serial modem should be considered as the data circuit-terminating equipment (DCE) and the external application or computer as the data terminating equipment (DTE).

6	7		8	9
1	2	3	4	5

1	DCD	4	DTR	7	RTS
2	RD	5	GND	8	CTS
3	TD	6	DSR	9	RI

The electrical characteristics of the serial port signals are shown below:

Pin	Signal	Dir	Voltage
			levels
1	DCD	O	> +4V
			< –4V
2	RD	O	> +4V
			< –4V
3	TD	I	> 2V
			< 0.8V
4	DTR	I	> 2V
			< 0.8V
5	GND	-	0V
6	DSR	O	> +4V
			< –4V
7	RTS	I	> 2V
			< 0.8V
8	CTS	O	> +4V
			< –4V
9	RI	O	> +4V
			< –4V

Description

Data carrier detect

Received data

Transmitted data

Data terminal ready

Ground connection Data set ready

Request to send

Clear to send

Ring indicator

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LZT 123 7361 R1A