This Part of IEC 62820 specifies the technical requirements for the composition, functions, performance, and test methods of general building intercom systems. This part is applicable to the general intercom systems for building entry in residential or commercial buildings. Door-Entry-System (DES) is a simple kind of convenient Building-Intercom-System (BIS) mainly for user s comfort. This document has classified the general building intercom systems into two grades in Part 1-1. Grade 1 adopts lower requirements to cover DES not used for relevant security applications while grade 2 adopts higher requirements for building intercom systems for security applications. Each grade may adopt different functional and performance requirements, test methods and normative references. NOTE The different requirements between grade 1 and grade 2 are summarized in Table C.1.