Zone Usage Measurement (ZUM) is the method by which
phone companies
A telephone company, also known as a telco, telephone service provider, or telecommunications operator, is a kind of communications service provider (CSP), more precisely a telecommunications service provider (TSP), that provides telecommunicat ...
in
California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
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
Lata (Hindi: लता) is a Hindu/Sanskrit Indian female given name, which means "creeper" and "vine". Lata may refer to:
Notable people named Lata
*Lata Bhatt (born 1954), Indian singer.
* Lata (born 1975), Musician.
*Lata Mangeshkar (1929–2 ...
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