Podcast question [telecom]

Hello telecom enthusiasts,

I'm a producer with Underunderstood , a podcast about questions that can't be answered with a simple Google search. We have over 500,000 downloads and were named to The Verge and HuffPost's best of 2019 podcast lists.

I'm working on a story about area codes which was brought to us by a listener. The question is about the area code assignments in Massachusetts. Specifically, when area codes were originally chosen, most metro areas allegedly got low numbers because they were easier to dial. However, in Massachusetts, this rule was notably violated: Boston got 617, whereas rural western Massachusetts got 413. Why did Boston get stuck with the high numbers, especially considering its importance to the history of telephony?

This seems to have been a persistent mystery. Mark J Cuccia brought up the question several times but seems to have never quite solved it:

(was it caused by a printing error?). He also wrote about an earlier proposed version of the nationwide numbering plan that was quite different:

I spoke with the author of this Quora answer

who said his source was a coworker who had previously worked at New England Telephone.

The decision seems to have been made between the publication of these two articles:

1946
1947

The plan was announced, I believe, in October 1947, although I do not have that document.

I'd love to find out whether there is a definitive answer to this as more historical documentation comes online.

Thank you for your consideration. You may also email me directly at snipped-for-privacy@underunderstood.com.

Adrianne