Ref: "Ap1400ProgGuide1_2.docx" Page 6 of 42
Document Revision: “1.2”
Document Date: “9 Apr. 2013”
Graphics may be combined with text printing as required. Large areas of solid dots are not
recommended, as they may cause overheating and shorten the head life: try shading.
Serial Interface
The default serial interface format for the Ap1400 series printers is 9600 baud, 8 data bits, 1 stop bit
and no parity. Other formats can be programmed into the printer at the factory or in the field, from the
host. A setup program, suitable for use with a PC, is available from Able Systems to simplify this
process.
Serial data is expected on Rx in RS-232C format with -12V meaning 'mark' or logical '1', and +12V
meaning ‘space’ or logical '0', with reference to the common ground. The serial data output line, Tx,
transmits XON/XOFF and status information to the host at the same baud rate and format as the
serial data input. The hardware busy line, Busy, is true (nominally -12V) when busy.
Some host equipment use a constant space condition (+12V) to indicate a reset condition or wait
state. Some battery powered host equipment present the same output signal when they go to sleep.
By default the printer will interpret this condition as a repetitive receive error, and will print multiple ‘?’
characters to indicate the fault. If required, the printer may be set to ignore this condition.
Data Buffer and Flow Control
The printer has a nominal 10k byte buffer which enables data to be received while previous lines are
being printed. The state of the data buffer is transmitted to the host as follows:
XOFF (13HEX) sent when buffer fills to 3/4 full;
XON (11HEX) sent when buffer empties to 1/4 full; and also after a controller reset.
The hardware busy line is set when 256 bytes of space remains; and incoming data are no longer
passed to the buffer (but may be processed) when 128 bytes remain. The hardware busy line goes
ready again when 384 bytes become free. Note that the buffer can become filled with non-printable
codes, in which case the controller will go busy.
The printer always transmits an XON character when it is powered on and is ready to receive data. It
is not necessary to select hardware or software handshaking. Both are active at all times.
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