Recommendation I.252.1 (11/1988): Call offering supplementary services: Call Transfer
recommendation/international standard from the International Telecommunication Union
ITU Telecommunication Standardization Sector
Call offering supplementary services: Call Transfer
Recommendation I.130 (11/1988): Method for the characterization of telecommunication services supported by an ISDN and network capabilities of an ISDN
Recommendation I.140 (11/1988): Attribute technique for the characterization of telecommunication services supported by an ISDN and network capabilities of an ISDN
Recommendation I.210 (11/1988): Principles of telecommunication services supported by an ISDN and the means to describe them
Recommendation I.252.2 (11/1988): Call offering supplementary services: Call Forwarding Busy (CFB)
Recommendation I.252.3 (11/1988): Call offering supplementary services: Call Forwarding No Reply (CFNR)