Step by step offices in the Bell System often used 11n instead of n11. This may have been legacy from candle stick phones where apparently a loose pulse could be inadvertently generated when going off hook.
Many places in the Bell System used 211 as a direct line to the long distance operator.411 was information and today "411" is a slang term for information, eg. "What's the 411 on the new movie?" I hear it on TV a lot but I don't hear it person. 611 was repair. That was dropped by the Baby Bells because it was supposedly "unfair" to competition, something that I don't understand. Years ago 611 was answered by technicians at a nearby test board, today it is some clerk far away.
Either 711 or 811 was a direct line to the testboard. This was used only by craft personnel when working at a subscriber site for testing.
In rural areas, the shown number in the phone book for FIRE was the fire chief's name and home phone.