Why was 911 decided to be the shorthand dial for emergency numbers? Why not other combinations that are easier to remember (e.g. 111, 123, etc.)?

Question

Why was 911 decided to be the shorthand dial for emergency numbers? Why not other combinations that are easier to remember (e.g. 111, 123, etc.)?

In: Other

Answer 1

Before tone systems, a dial phone simply put voltage pulses on the line, 111 on a dial phone can be mimicked by stray single pulses. Some choices may have been arbitrary but part of it was to be easy to dial and not to create spurious calls on an early network with electrical noise.

Britain uses 999 and the EU 112 (also works in Britain)