Although this site is devoted to one specific AT&T product, there are numerous other sites that provide additional resources that may be of interest.
AT&T Bell Labs and Lucent Technologies by Marc Polster
AT&T Labs Legacy — the official site of the current AT&T Labs
The AT&T Archives & History Center — an interview with Sheldon Hochheiser, AT&T historian
The Bell System Memorial — a website devoted to preserving documents, memorabilia, and information about The Bell System
Telephone World — another website devoted to all things telephone