Zone Usage Measurement (ZUM) is the method by which
phone companies
A telecommunications company is a kind of electronic communications service provider, more precisely a telecommunications service provider (TSP), that provides telecommunications services such as telephony and data communications access. Many t ...
in
California
California () is a U.S. state, state in the Western United States that lies on the West Coast of the United States, Pacific Coast. It borders Oregon to the north, Nevada and Arizona to the east, and shares Mexico–United States border, an ...
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 (21 km) radius from the point of origination. The ZUM zone beyond that is divided into ZUM1 (12-13 mile radius), ZUM2 (14-15 mile (24 km) radius), and ZUM3 (15-16 mile (26 km) radius). Beyond the ZUM zone calls are considered intra-
LATA
Latha (Hindi: लता, Kannada: ಲತಾ) is a Hindu Indian female given name, which means "creeper" and "Durga". Latha may refer to:
Notable people named Lata
*Lata Mangeshkar (1929–2022), Indian singer.
*Lata Bhatt (born 1954), Indian sin ...
or inter-LATA.
[AT&T White Pages Directory, San Fernando Valley edition, August 2014-2015 issue, "AT&T Service Area" and "Local Toll Calling Rates and Calling Plans" (p. A25).]
Background
Local Access and Transport Areas (LATA) were created after the breakup of the Bell System. They are sometimes called service areas, or local toll calling areas. California, for example, is divided into 11 service areas. Calls made to places within the same service area break down as follows:
Rural
:Local Calls: 0–12 miles
:Local Toll: 13+ miles (within service area)
Urban
:Local Calls: 0–12 miles
:Zone Usage Measurement (ZUM), or Zone 3: 13–16 miles
Local Toll
17+ miles (within service area)
Calls within each area, up to about 12 miles, are local calls. In metropolitan areas, calls between 13 and 16 miles are Zone Usage Measurement (ZUM) Zone 3 calls. All other calls within each Service Area are now referred to as Local Toll calls. In non-ZUM areas Local Toll calls start at 13 miles.
Notes
References
AT&T CALIFORNIA GUIDEBOOK, PART 4 - Exchange Access Services, SECTION 2 - Exchange Lines and Usage
{{DEFAULTSORT:Zone Usage Measurement (Zum)
Telephony