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Input/Output Signals :
DATA 1 ~ 8 (Printer ← Host)
Input data signals for the 1st to 8th bits.
Logic 1 is "High" level.
Min. data pulse width of 2.5 µsec.
DATA • STROBE (DATA • STB) (Printer ← Host)
Synchronizing signal for reading the above data.
Normally at "High" level. The data is read at the rise of the Low level pulse.
Minimum data pulse width of 0.5 µsec.
BUSY (Printer → Host)
This signal indicates that the printer is in a BUSY state.
When initialized after power on, the printer becomes ready to receive data and turns the
signal to "Low" level.
The signal turns to "High" level (in a BUSY state) when data is set from the host (at the fall
of the DATA • STB signal).
The signal turns to "Low" level when the printer reads the data.
When the blank positions in the receive buffer are 512 bytes or less, the printer keep the
signal at "High" level (in a BUSY state) for 10 seconds when data is set from the host, to
extend the data read interval.
When there are no blank positions in the receive buffer, the printer stops reading data.
Then, it keeps the signal at "High" level (in a BUSY state) until there are blank positions in
the receive buffer when data is set from the host.
The signal is kept at "High" level (in a BUSY state) until the current state (one of the
following states) is reset.
• PAUSE state caused by the PAUSE key
• Paper End state
• Ribbon End state
• Head Open state
• Printer Error state
• Initialization in progress upon receipt of the INPUT • PRIME signal
ACKNOWLEDGE (ACK) (Printer → Host)
This signal indicates that the printer has read the data set by the host and is ready to
receive the next data.
Normally at "High" level. It is at "Low" level for about 5 µsec. after the fall of the BUSY
signal.
The host should usually set data after the ACK signal turns from "Low" to "High" level.
If the host ignores the ACK signal and sets the next data while the ACK signal is at "Low"
level, the signal will further continue to be at "Low" level for about 5 µsec. after the fall of the
BUSY signal (the data will still be received normally in this case).
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