Delete comment from: Ken Shirriff's blog
An interesting article, I will wait to continue.
I want to note that the static indication was applied due to the fact that in the case of multiplexing, the visible brightness of the indicator is significantly reduced. This may require an increase in supply voltage, i.e. installation of keys with an open collector and complications of circuitry, volume and mass of the device. Reliability will also decrease.
As for transitional transformers, they can work not only as an isolation, but also as a way of matching signal levels with other equipment, for example, with the same keys with an open collector.
Also, in on-board equipment it was considered more reliable to use soldered wire harnesses instead of board connectors. It should be understood that this equipment was intended to be used once and was not supposed to be repaired.
Jan 20, 2020, 7:42:26 AM