Some Ericsson AGF information

Warning: unfinished

Going solely off vibes it feels like a middle-ground between the step-by-step and the Bell System’s Panel Switch, though it’s much more like the panel than the step-by-step. Just like the panel it has (in normal configurations) three stages of selectors, connection establishing devices (called “register sets” in AGF, “senders” in panel) and sequence switches controlling selectors. There’s more things too but those are the easiest to list and the ones I know for a fact are similar in both systems.

Having been called “the first blade servers” by random people I know, the 500-line selectors were very modular (attached to the system only by a plug and easily removed from a rack) and quite simple in design. Unlike most of its contemporaries it would not be too difficult to manufacture a small run of 500-line selectors for restoration use. There were two variants, line finders and not line finders. Line finders have an extra two conductors on the armature, one of them at the front to tell if it’s reached a group containing a line needing service. The non-line finders instead have a cam that a switch runs along providing revertive pulses to indicate to the register set how far it’s moved.