NCR 7169 - Print Speed and Timing

Communication 4-119
RS-232C Interface
The RS-232C version of the 7169 printer offers the standard options, which are selectable
in the Diagnostic mode. For more information, refer to Communication Interface Modes on
page114.
Print speed and timing
The fast speed of the printer requires its printer application to send data to the printer at
least as fast as the data is printed. The application must also allow receipt lines to be
buffered ahead at the printer, so the printer can print each line immediately after the
preceding line, without stopping to wait for more data. Ideally, the application sends all
the data for an entire receipt without pausing between characters or lines transmitted.
If the application sends data at 9600 baud and pauses between lines for as little as
50 milliseconds, the printer will not be able to print at full speed. But, if the application
sends data at 19.2 kilobaud and does not pause between lines, the printer will be able to
print at its full speed of 1020 lines/minute.
The following table shows that with a pause of 50 milliseconds after each line, the
transmit time equals or exceeds the print time, which slows down the printer, regardless
of the baud rate.
Char/Line Lines/Receipt
Transmit Time:
9600 baud
Transmit Time:
19.2 kilobaud
Print Time
20 20 1.4 seconds 1.2 seconds 0.2 seconds
20 40 2.8 seconds 2.4 seconds 0.4 seconds
44 20 1.88 seconds 1.44 seconds 0.2 seconds
44 40 3.76 seconds 2.88 seconds 0.4 seconds