A serial daughter board for the
(see above) providing two 8250 UARTs
with RS232 interfaces. These UARTs have programmable baud rates, stop bits,
parity, stop bits etc, and also spare user-programmable input and output bits.
80-BUS Speech board, using the National Semiconductor Digitalker chip set.
This card has a limited on-board vocabulary contained in ROM, and making it
say anything outside of this limited library is extremely difficult. Produced
by Arfon Microelectronics, who unfortunately went into receivership. Boards
MAY still be available from one or two dealers.
Light pen, suitable for use with the
GM837 boards. Again, as
this was an Arfon product, and so unfortunately it may prove impossible
to obtain any more.
Original 59 key parallel interface keyboard from Gemini for use with the
video boards. Although only 59 physical keys, all 128 possible 7-bit
ASCII codes can be generated. Discontinued (see
A small board containing a Nat. Semi. 58174 Real Time Clock chip with battery
back-up. Connected to the system via a Z80 PIO. Only available in kit form.
Special version of the Gemini
keyboard for the Danish market. Replaced by
low profile version.
80-BUS A/D convertor board. Originally produced by IO Research, but later
taken over by Gemini. This board provides 8 channels, each of 8 bit
resolution. Input range is 0 – 5 volts with over-voltage protection.
Conversion time is approx. 30uS, including sample and hold phase. Support
for vectored interupts, and on-board prototyping area.
A single/twin 5.25″ disk drive unit using one or two Micropolis drives and
PSU. For use with
Available in single and double sided
96tpi versions. Capacity in double density mode is 400K single sided, 800K
double sided (formatted).
80-BUS CMOS RAM board from Microcode Processes. Contains 32K of battery-backed
static RAM to give 1000 hours of memory retention during power-down
periods. Flexible address decoding and Page Mode operation, but does not
support Extended Addressing.
Gemini’s 87 key keyboard (parallel interface) for use with the
video boards. The keyboard has a 57 key main cluster, plus 11 function keys,
4 cursor keys, and 15 key numeric pad. Theses latter 30 keys may ALL be user-defined
video boards) in both their normal and shifted modes. Replaced by
low profile versions.