Host protocol, Xon/xoff, Etx/ack – Printronix L5020 User Manual
Page 74: Ack/nak

Chapter 3
Printer Configuration
74
Host Protocol
The Host Protocol parameter allows you to select the software flow
control protocol used for communications between the printer and
the host computer. You can also turn off software flow control.
Values: None, XON/XOFF, ETX/ACK, ACK/NAK, ENQ/ACK,
SERIES 1, 1 CH, or SERIES 1, 2 CH.
This parameter must be set to match your host computer.
The actions for each of the parameter values are as follows:
None (default)
When you select None, the software flow control between the
printer and the host is disabled.
XON/XOFF
NOTE: XON means “transmit on;” XOFF means “transmit off.”
When you select the XON/XOFF protocol, the printer does the
following:
•
When not ready to receive data (i.e., offline or full data buffer),
the printer sends ASCII code DC3 (Device Code 3, hex 13,
XOFF) to the host.
•
When ready to receive data (i.e., online and empty data buffer),
the printer sends ASCII code DC1 (Device Code 1, hex 11,
XON) to the host.
ETX/ACK
The ETX/ACK protocol enables 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
acknowledges the signal, thereby indicating it has received the
entire block of data.
ACK/NAK
The ACK/NAK protocol gives the printer a means to acknowledge it
has either accepted a transmission (ACK) or did not receive a
transmission (NAK).