Wednesday, June 6, 2012

Today's Trivia: Why did Bell Labs create phone numbers of 7 digits - 10 digits?

andrewchen great answer. Why did Bell Labs create phone numbers of 7 digits - 10 digits? - Quora, May 22 15:33:06 from Timely by Demandforce


  1. Great post. I'll take it a step further:

    The original area code assignments all had either a '1' or a '0' as the middle digit. Certain areas were given '1', and certain areas '0' for a reason. What differentiated who got which one, and why?

  2. Interesting... especially the high population areas getting lower (faster) numbers.

    "In 1947, states and provinces that had a single area code we assigned three digit codes with 0 as the middle number, such as 203 for Connecticut and 305 for Florida . There were 86 area codes at that time.

    States and provinces that had more than one area code distributed to them were given three digit codes with 1 as the middle number, such as 916 and 213 for various sections of California , and 212 and 518 for various sections of New York .

    The first and third digits were allotted according to population density in the city or region the area code was going to, with the most populated areas getting the lowest numbers. The New York City area, for example, was assigned 212, while the surrounding suburbs were assigned 914.

    The rationale for this “low number/high population” scheme was based on the fact that phones had rotary dials in those days. Lower numbers resulted in shorter “dial pulls” so it was reasoned that the regions with the most people in them should require the least “work” to call."