Printronix P5000LJ user manual Interface Type, Data Protocol, Baud Rate

Chapter 4 Host Interface Menu

Interface Type

Allows you to select either the RS-232 (the default) or RS-422 serial port interface.

Data Protocol

You can select one of the following serial interface protocols to meet the host interface requirements.

•XON / XOFF. The default. The printer controls the flow of communication from the host by turning the transmission on and off.

In some situations, such as when the buffer is full or the timing of signals is too slow or too fast, the printer will tell the host to stop transmission by sending an XOFF character.

An XOFF character is sent when the number of empty bytes in the buffer is less than or equal to 25 percent of the buffer size.

If the host keeps sending data after an XOFF is sent, the printer firmware will continue to send an XOFF for every 16 characters received.

When cleared, the printer will resume receiving data (XON). The data does not have any End of Text codes; XON / XOFF is a non-block protocol.

•ETX / ACK. End of Text / Acknowledge. The host controls the flow of communication to the printer by sending a block of data and ending the block with an End of Text (ETX) signal. When the printer receives the ETX signal, it will acknowledge the ETX, thereby acknowledging it has received the entire block of data.

•ACK / NAK. ACK means acknowledge; the device acknowledges it has accepted a transmission. NAK means a negative acknowledge; the device did not receive the transmission.

•DTR. Data Terminal Ready. The printer controls the data flow by sending this hardware signal to the host. If there is enough room in the printer buffer, the printer will send a high signal. If the buffer is full, the printer will send a low signal. DTR tells the host if it is safe to send more data. If the host sends data during an unsafe condition, data will be lost.

Baud Rate

Sets the baud rate of the serial interface in the printer. Baud rate is the speed at which serial data is transferred between the host computer and the printer. The choices for the RS-232 and RS-422 interfaces are 600, 1200, 2400, 4800, 9600, 19200, and 38400. The default is 9600 baud.

Note	If you select a baud rate that is 19200 or greater, you may need to increase
	the Buffer Size in K parameter from the default (1 Kbyte) to improve
	performance.

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