Lapsley co-authored RFC 977, Network News Transfer Protocol (NNTP), an Internet standard for transmission of USENET news articles, and was the primary developer of the NNTP reference implementation, nntpd. After leaving Berkeley he co-founded Berkeley Design Technology, Inc., a digital signal processing technology advisory firm, and is the author of a book on DSP processors. He later co-founded SmartTouch, a biometric financial transaction processing company.
^Network News Transfer Protocol: A Proposed Standard for the Stream-Based Transmission of News, Request for Comments 977, Brian Kantor and Phil Lapsley, February 1986
^DSP Processor Fundamentals: Architectures and Features (Ieee Press Series on Signal Processing), Phil Lapsley, Jeff Bier, Amit Shoham, and Edward A. Lee, IEEE-Wiley, February 1997, ISBN 978-0-7803-3405-2