It explains the architecture of the 7011/250 in detail. When I was much younger I was working with a group to get Linux on there. We got to the point of making a boot floppy that would display a 3 digit number on the front panel.
That's not accurate - when a telephone company registers a block of numbers (at least in the US), you specify if it's landline, pager, VoIP, cellular, etc.