Printronix T4204 - Manual (Page 83)

HOST INTERFACE Menu
83
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 negative acknowledge; the device
did not receive the transmission.
• SERIES1 1 CHAR. The printer controls the flow of communication from
the host by turning the transmission on and off using response characters
sent to the host. If the number of valid bytes in the buffer reaches 75
percent of the buffer size, the online or offline and buffer full response
character is sent. If the buffer is completely full, an online or offline buffer
full response is sent every time a character is sent from the host.
Whenever the printer state changes to online or offline, the appropriate
response character is sent. If the idle response option is enabled, the
printer will send a response character every two seconds while the
number of valid bytes in the buffer is less than 75 percent of the buffer
size. If a poll character is received (configurable from the Poll Character
xx Hex option on the front panel from 00 through FF hex), the printer will
send a response character
n milliseconds later (configurable from the Poll
Character xx MS on the front panel from 0 through 30). This n
milliseconds is called the poll delay. The poll character will be removed
from the input data stream and will not be processed. This may cause
problems with the transmission of binary data (e.g. control codes, bit
image, etc.). If a poll delay is started due to the receipt of a poll character
and another poll character is received, the second poll character has no
effect, and is removed from the input data stream. If a transition (from
buffer full to empty or online to offline) occurs during a poll delay, the new
printer state will be sent at the end of the poll delay.
The response characters are described in Table 2.
• SERIES1 2 CHAR. This protocol behaves exactly the same as the
Series1 Char except there is a two-character response to the host. The
response characters are described in Table 3.
Table 2. Series1 1 Char Response Characters
Printer State Response
Online and Buffer Empty CR
Online and Buffer Full 3
Offline and Buffer Empty 0
Offline and Buffer Full 2