Chapter 4 HOST INTERFACE
98
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 hex 0 through FF), 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.
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