Printronix P3000 Series manual RS-232 Serial Interface Protocols, Serial Interface Pin Assignments

Received Data – Serial data stream to the printer.

Transmitted Data – Serial data stream from the printer for transmitting status and control information to the host. Subject to protocol selection.

Request To Send (RTS) – Control signal from the printer. Subject to configuration.

Clear To Send (CTS) – Status signal to the printer indicating the host is ready to receive data/status signals from the printer.

Data Set Ready (DSR) – Status signal to the printer indicating the host is in a ready condition.

Carrier Detect (CD) – Status signal to the printer. The ON condition is required for the printer to re- ceive data. Available as a configuration setup option.

Reverse Channel – Control signal from the printer. Subject to configuration.

Data Terminal Ready (DTR) – Control signal from the printer. Subject to configuration.

Table 7–3. Serial Interface Pin Assignments

INPUT SIGNALS		OUTPUT SIGNALS
SIGNAL	PIN	SIGNAL	PIN
Received Data	3	Transmitted Data	2
Clear To Send	5	Request To Send	4
Data Set Ready	6	Reverse Channel Send	11, 14
Carrier Detect	8	Data Terminal Ready	20
		Chassis Ground	1
		Signal Ground	7

RS–232 Serial Interface Protocols

The following serial interface protocol characters are available. The protocol is configuration selec- table from the control panel to meet host interface requirements.

X–ON/X–OFF– The printer transmits an X–ON character (hex 11) when entering the on line state or when the buffer is almost empty. The printer transmits an X–OFF character (hex 13) when entering the off line state or when the buffer is almost full.

DTR (Data Terminal Ready) – Control signal from the printer. (Subject to configuration.) Configu- rations include: always true, always false, true if on line and buffer not full, and true if off line or buffer almost full. When the printer is off line or when its buffer is almost full, DTR is toggled. When the printer is ready to receive data, DTR is toggled back.

ETX/ACK – With ETX/ACK protocol selected, the printer interface operates in a block structured mode. The host sends a block of data in response to an ACK character (hex 06) sent from the printer. The host marks the end of the block of data with an ETX character (hex 03). When the printer recog- nizes the ETX character, the printer releases the data block to be printed and checks the space available in the buffer. If space is available for the next block of data, the printer sends ACK to the host. If space is not available, the printer withholds ACK until sufficient space is available.

Interfaces 7–11