(2)Ready/Busy system (see the figure)
This is a control system in which the DTR signal is output at Ready (High)/Busy(Low) level.
Requirements of DTR "High":
•When the printer is "on line."
•When the remaining buffer is less than 2K bytes.
However, when the remaining buffer of less than 2K bytes is detected, the printer keeps a "Low" level until the remaining buffer is 4K bytes or more.
•When printer alarms such as the printer switched to "off line" occur.
