CONTENTS



1.    I.500 - General structure of the ISDN interworking Recommenda-
tions.



2.    I.510 - Definitions and general principles for ISDN interworking.



3.    I.511 - ISDN to ISDN layer 1 internetwork interface.



4.    I.515 - Parameter exchange for ISDN interworking.



5.    I.520 - General arrangements for network interworking between 
ISDNs.



6.    I.530 - Network interworking between an ISDN and a public-
switched              telephone network (PSTN).



7.    I.540 - (see X.321).



8.    I.550 - (see X.325).



9.    I.560 - (see U.202).





















2.4	Protocol level



	In the protocol level, the protocols listed are those that appear at the Ref-
erence points Kx and Nx.



末末末末末 

















2.5	Recommendations which relate to interworking are shown in 

Figure1/I.500 and are assigned to the levels in section 2. As the contents 
of some Recommendations cover more than one level these Recommen-
dations appear at each level to which they relate.



3.	References



	The References are general to all I.500 Recommendations and are to be 
read in conjunction with Figure 1/I.500, where the organization of ISDN 
interworking Recommendations is shown.



3.1	Interworking



	X.300-Series	Interworking between public networks, and between public 
networks and other networks for the provision of data transmission ser-
vices 



	I.324			ISDN architecture functional model



	I.340			Connection types/elements for ISDN-ISDN interwork-
ing



	X.31			Support of packet-mode terminal equipment by an ISDN



	X.81			Interworking between an ISDN circuit switched and a 
circuit switched public data network (CSPDN)



3.2	Services and network capabilities



	X.1			International user classes of service in public data net-
works and integrated services digital networks (ISDNs)



	X.2			International data transmission services and optional 
user facilities in public data networks and ISDNs



	X.10			Categories of access for data terminal equipment (DTE) 
to public data transmission services



	I.122			Framework for providing additional packet-mode bearer 
services



	I.200-Series	Service aspects supported by an ISDN 



	I.310			ISDN - Network functional principles



	I.320			ISDN protocol reference model



	I.325			Reference configurations for ISDN connection types



	I.411			ISDN user-network interfaces - reference configurations



	I.412			ISDN user-network interfaces

				Interface structures and access capabilities



	I.420			Basic rate user-network interface



	I.421			Primary rate user-network interface



	I.441			ISDN user-network interface data link layer 	(Q.921)		
specification



	I.451			ISDN user-network interface layer 3 specification

	(Q.931)



3.3	Signalling



	Q.700			Network protocols (MTP, ISUP, etc.)



	Q.120-Q.180		Specification of Signalling Systems No. 4 and No. 5.



	Q.251-Q.300		Specification of Signalling System No. 6



	Q.310-Q.490		Specification of Signalling Systems R1 and R2



	X.75			Packet switched Signalling System between public net-
works providing data transmission services



	X.25			Interface between data terminal equipment (DTE) and 
data circuit equipment (DCE) for terminals operating 
in the packet-mode and connected to public data net-
works by dedicated circuits



	X.71			Decentralized terminal and transit control signalling sys-
tem on international circuits between synchronous 
data networks



	U.12			Terminal and transit control signalling system for telex 
and similar services on international circuits (type D 
signalling)



3.4	Rate adaptation



	I.460			Multiplexing, rate adaptation and support of existing 
interfaces



	I.461 (X.30)	Support of X.21, X.21bis and X.20bis based DTEs by an 
ISDN



	I.462 (X.31)	Support of packet-mode terminal equipment by an ISDN



	I.463 (V.110)	Support of DTEs with V-Series type interfaces by an ISDN



	I.464			Multiplexing, rate adaptation and support of existing 
interfaces for restricted 64 kbit/s transfer capability



	V.120			Support by ISDN DTEs with V-Series type interfaces 
with provision for statistical multiplexing



3.5	Numbering



	X.121			International numbering plan for public data networks



	X.122			Numbering plan interworking between a PSPDN and an 
ISDN or PSTN in the short-term



	I.331 (E.164)	Numbering plan for the ISDN era



	E.166			Numbering plan interworking in the ISDN era



	I.330			ISDN numbering and addressing principles



	I.332			Numbering principles for interworking between ISDNs 
and dedicated networks with different numbering 
plans



	F.69			Plan for telex destination codes