Canon 161

The 161 is Canon’s second electronic calculator, a direct development of the 130, released in late 1965 just a year after the 130. It extended and improved the architecture of the 130 and addressed a number of engineering deficiencies. The main improvements and differences were:

number magnitude extended to 16 digits
storage register for intermediate results
total accumulation
removable PCBs
service monitor/controller port

While the 161 was a useful improvement from the 130, it used nearly 800 transistors and over 2000 diodes. The extraordinary parts count was the consequence of its counter architecture where every digit was held in its own flip-flop. The limits of this architecture were plain to see and in early 1965 Canon released the model 167, its first serial architecture calculator with a magnetic drum memory. The 161 lived on until 1968 when it was replaced by the 161S, a serial architecture, IC and delay line based machine.