1 Answers
Zone Usage Measurement is the method by which phone companies in California distinguished "local" service from "long distance" service within the service area to which local phone companies used to be restricted.
Usually the local calling area includes a 13-mile radius from the point of origination. The ZUM zone beyond that is divided into ZUM1 , ZUM2 radius], and ZUM3 radius]. Beyond the ZUM zone calls are considered intra-LATA or inter-LATA.
5 views
Answered