This Recommendation describes the subscriber side interface characteristics of digital exchanges. It applies to digital local and combined exchanges for telephony in Integrated Digital Networks (IDN) and to local and combined exchanges in an Integrated Services Digital Network (ISDN), and also to mixed (analogue/digital) networks.
This Recommendation is part of the Q.510-Series of Recommendations which defines the interface functions for digital exchanges in Integrated Digital Networks (IDN), mixed analogue/digital networks, 64 kbit/s-based Integrated Services Digital Network (ISDN).