The 9866 printer was fairly integral to operation of the 9830. Program listings, most program output, and trace-mode operation relied on having a 9866 attached, or a device interface for another printer.

The interface to the 9866 is very simple: 7 parallel data lines carrying ASCII data, a strobe and ack, all at TTL levels. It should be simple to connect a once-common parallel printer, the more difficult part being obtaining the military style-connector to mate with the connector on the rear of the 9830.

The Mimic66

The Mimic66 is a simple alternative to the 9866 that interfaces the 9830 printer output to a host computer set up to simulate the printer, allowing display and capture of everything the 9830 prints.

The Mimic66 could be built as a separate unit that plugs into the rear-panel 9866 barrel connector, in the form shown it has been built as a plug-in module that occupies an I/O slot, although it is not a full I/O interface. Inside the 9830 the small edge connector that leads to the rear-panel 9866 barrel connector is unplugged and the mimic substituted. This disables normal use of a 9866 of course, but if one doesn't have a 9866 that doesn't matter. The small number of edge pins that plug into the external I/O bus just pick up power for the solitary IC on the Mimic66.

The Mimic66 has been used with a Raspberry Pi as host, with a simple Python program on the RPi taking the output from the 9830 and displaying it. The link to the host is a simple clocked serial line, the same as that used with the MPSI.

Note that the MPSI incorporates equivalent functionality to the Mimic66.