The following is a chronological listing of date of installation and location of Western Electric/Northern Electric/North Electric #4 Crossbar Toll Switches.This is a summary of the #4-type Crossbar (XB) Toll machine's history.Actually, the Card Translator hadn't even been invented/developed at the time (1943).However, by 1949 the Card-Translator was already under development by WECO/Bell-Labs.Now, as for the chronological lists and additional notes: Listed below are the first six #4-XB Toll machines.WECO manufactured and installed them for service without any 'Card-Translator' Boxes.If the switch were a Cl.3 (Primary) or a Cl.4 ('ordinary' toll office), the additional digit(s) after the NPA code in the 'trailer' would be a '4' or above.There were a few deviations from this "rule", but for the most part, it was followed.
[Class-1 switches are "Regional"- there were twelve regionals within the DDD Network, the one not in any of the below lists/charts is that of Regina 1 SK, REGNSK0101T, which was a XB-Tandem (NOT a #4-type XB) installed in Nov 1955; Class-2 switches are "Sectional", more numerous than "Regionals"; Class-3 switches are "Primary", more numerous than "Sectionals"; Class-4 switches are "ordinary toll switches", most numerous; One particular #4A machine (Dallas-Taylor LOCAL, DLLSTXTA02T) was STRICTLY used as a local-area tandem and is shown as 'L' for its hierarchical class/rank in the network].
San Bernardino CA _IS_ the name of the GTE-ratecenter; Norway is a 'locality' within the Sheridan IL GTE-ratecenter.
These two #4As are _NOT_ noted in the lists below as "independent", since they were OWNED by AT&T, and NOT GTE, even though they were physically located within GTE's territory.
Also, it didn't really matter what type of 'equipment' the toll or tandem switch had for the trailer digit(s) - all that mattered was the NPA the switch was located in and the switch's "rank" in the network's hierarchy.
Also, the NPA's digits listed here as quoted in the trailer may not necessarily have been the actual NPA at the time of switch installation, nor during continued service of the switch, due to various NPA-splits throughout 1950's, the 1965 FL 305/904 split, and the 1973 VA 703/804 split, or any of the 1980's/early-90's era NPA-splits.
With divestiture, management of the CLLI code assignments went with Bellcore (now Telcordia) Language Standards; ALSO, it _IS_POSSIBLE_ that a CLLI code used at one time for a switch that has been retired _COULD_ be re-used for a new switch] - the third column is the "rank" or "classification" of the switch within the DDD network hierarchy, _AS_OF_ the 1976 timeframe.