1 overlined signal names indicate that the signal is true when the signal level is low.

    2 when the interface buffer is full except for the last character, busy will not be **) reset. busy will be reset when space is available again for least 256 characters in the interface buffer. while the printer is offline (stop mode) busy remains active until the printer enters the online state again.

    - maximal transfer speed

    the maximum throughput for data transfer is 5,000 characters per second.

    3.1 transmission protocol description

    after power-on the pe (paper end) signal is set to logic 0 and the select and ˉ fault signals are set to logic 1.

    the printer is now on-line and ready to receive data.

    timing

    the host sets a print/control character to the 8 data lines.

    after a time delay of a minimum of 0.5 μs, the host sends aˉ strobe pulse of a minimum of 0.5 μs. the print/control character is accepted into the interface buffer and the printer transmits a busy signal to the host. when the data byte is accepted into the interface buffer the printer transmits a busy signal and an ˉ ackn pulse.

    the ackn pulse informs the host that the data has been received and that the printer is ready to receive new data.

    if the interface buffer is full except for the last character the busy is not reset in order to stop the data transfer from the host. the busy signal is only reset if space is available in the interface buffer for a minimum of 256 characters. when pressing [start/stop] the busy remains high and no ˉ ackn is sent. provided a minimum of 256 characters are available in the interface buffer, pressing [start/stop] will reset busy and transmit the ˉ ackn pulse.

    3.2 timing diagram