1998ETSI ETS 300 099-1998 Integrated Services Digital Network (ISDN); Specification of the Packet Handler Access Point Interface (PHI) (Second Edition;)
1997ETSI PRETS 300 099-1997 Integrated Services Digital Network (ISDN); Specification of the Packet Handler Access Point Interface (PHI) Second Edition
1996ETSI PRETS 300 099-1996 Integrated Services Digital Network (ISDN); Specification of the Packet Handler Access Point Interface (PHI) Second Edition
1991ETSI PRETS 300 099-1991 Integrated Services Digital Network (ISDN) Specification of the Packet Handler Access Point Interface (PHI)