180 channels. Replaced the Duet in the range.
From John Wright:
The first Gemini’s (1983/4) were built with raw Galaxy parts (inc the Advance PSU) and were expensive to make compared with Gemini2 which integrated the panel communications interface (which only had to run a few cm not the Kilometre spec of Galaxy comms) into the memory card and also replaced the [expensive] Advance PSU brick with a cheap (then new & novel) single board unit.