Bidirectional Parallel Interface; Parallel Interface Communication Mode - Citizen PPU-700 Command Reference Manual

4.2 Bidirectional Parallel Interface

Overview
The interface of the printer is a Level-1 compatible device according to IEEE-P1284. It supports the
communication modes described in 4.2.1 below.

4.2.1 Parallel Interface Communication Mode

The parallel interface of the printer provides three communication modes as outlined below. When
the printer is turned on or reset, it defaults to Compatibility mode.
• Compatibility Mode
Data is transmitted from the host to the printer in units of one byte. Usually, this mode is used
for data transmission. You may switch to the other modes from Compatibility mode.
• Nibble Mode
Data is transmitted from the printer to the host in units of four bits. The data transmission from
the printer uses a status signal line. To send one byte of data in this mode, two sets of four-bit
data are sent consecutively.
• Byte Mode
Data is transmitted from the printer to the host in units of one byte. Data transmission from the
printer uses an 8-bit data signal line. For Byte mode, the host must be capable of toggling the
signal direction over the 8-bit data signal line. Communication from the host to the printer is
called Forward mode, while communication from the printer to the host is called Reverse mode.
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