Notes on the Network

Notes on the Network is a publication of the American Telephone & Telegraph Company that outlines the state, technology, and operating principles of the public switched telephone network in the Bell System in the United States and Canada, and for the entire North American Numbering Plan territory.

The origins of publication date back to 1945 as Nationwide Operator Toll Dialing.[1] AT&T published an extensive edition in 1955 under the title Notes on Nationwide Dialing, and additional editions as Notes on Distance Dialing in 1956, 1968, and 1975. The first use of the title Notes on the Network was for the 1980 edition.[2]

This document was maintained and published by Bell Communications Research (BELLCORE) in 1983 and 1986, 1990, 1994, and 1997. The 1983 and 1986 versions were known as Notes on the BOC Intra-LATA Networks, while the 1990 and 1994 editions had the title BOC Notes on the LEC Networks. The 1997 issue was entitled Bellcore Notes on the Networks.

Bellcore was sold in 1999, and the new name for the company became Telcordia. A new edition (Issue 4) was published in 2000 as Telcordia Notes on the Networks, which is the most recent version, as of 2017. Between 1999 and 2002, Telcordia also published a series of twenty-one topic-specific modules individually available, or for sale as a set, known as the Telcordia Notes On... Technology Series, which have also not been updated since.

In 1983, shortly before the 1984 divestiture of AT&T, Telecom-Canada published Digital Network Notes, an update and companion volume to the 1980 AT&T Notes on the Network, with more specific information for the Canadian territory.