CoS (Class of Service)

CoS (Class of Service) is a designation in E9‑1‑1 that defines the service category of the telephony service. A few examples are residential, business, Centrex, coin, PBX, VoIP and wireless Phase II (WPH2).

Related Terms:

Fixed (Static)

VoIP Class of Service sold as not having nomadic capability. Refers to an IP end-point that cannot move, is always in same location and always accesses a network from the same point.

FX (Foreign Exchange) Service

A telephone line switched in an exchange or central office other than the exchange or central office area in which the telephone is located.

Relevant NENA Documents
Note: To find and download the document, copy the document number (like NENA-STA-010) from below and search the NENA Standards and Documents page.


NENA-STA-015, NENA Standard Data Formats for 9-1-1 Data Exchange & GIS Mapping