Telephony
Phone Losers of America (PLA)
Sigtel (defunct) had hard-to-find information on vinatage communications equipment and technology [archive] including a telephone technology index [archive]
Local guides
tory.info/">Atlanta Telephone History
Film
Collections of vintage telephone “educational” shorts, burned to DVD, are readily found on eBay.
Online movie: Vintage Telephone Equipment Line Repair & Floods (1938)