GE GFK-2251 manual Serial Communication Ports, RS-232C Name Pin Assignment

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Serial Communication Ports

The COM1and COM2 serial ports are available on the side panel. The COM3 serial port is used by the touchscreen and is not accessible to the user. The standard 9-pin D-sub connector pin out is shown below.

RS-232C Name	Pin	Assignment
CF	1	DCD (Data Carrier Detect)
BB	2	RX (Receive Data)
BA	3	TX (Transmit Data)
CD	4	DTR (Data Terminal Ready)
AB	5	GND (Signal Ground)
CC	6	DSR (Data Set Ready)
CA	7	RTS (Request to Send)
CB	8	CTS (Clear to Send)
CE	9	RI (Ring Indicator)

Shielding

The D type connector covers should be metallized plastic or die cast metal and terminated with 360-degree termination of the shield, as illustrated in Figure 4-3 below.

Figure 4-3. High Frequency Grounding

Grounding

Serial cables (COM1 and COM2) must be shielded and grounded in order to maintain CE Mark compliance, provide higher EMC immunity, and satisfy the requirements of IEC/EN61000-4-4 and IEC/EN61000-4-5. The shield conductor should remain continuous to the unit, and insulation should be removed only at the grounding point. The grounding should be such that a 360-degree contact is made to the cable shield. Figure 4-4 shows an example with the insulating cover of the cable stripped back.

GFK-2251 Chapter 4 Connectors and Cabling 4-7