Unsure of your question Uppo?
A and B base refer to dispatching schemes. They are basicall identical, except A base was used mostly on touch button systems, and had multiple diagnostic cards you could plug into the card rack, and B Base was used with regular push buttons, and had one diagnostic board.
Both were based on VIP 260 logic, but transferred from relay form to DTL logic. (DTL = Diode Transistor Logic)
And to confuse things more, there was a CB base. Basically a B base dispatcher, but additonal boards that read flags in the hatch for Selector functions. Basically the 1st Otis that I'm aware of that did not have a mechanical selector.
Thanks broke i think you answered my question. I've worked on the touchbutton control(nightmares they are) feeding multiple cards on the lift no1 selector. I'm pretty sure this was the only high rise type here, with normal button style button types used with a geared machine and selector version for small applications. The next generation of otis lifts were the 401's and no cb base types. I've just read over the time posters stating a or b base and not really sure what they were referring to. Thanks mate.
