CONTENTS

 1     Introduction
 2     Circuit witched data transmission service
 3     Packet switched data transmission services
        3.1     Direct access to a packet switched data transmission service
        3.2     Port access to a packet switched data transmission service (user classes of service 20-26 and 29)
        3.3     Port  access to a packet switched data transmission service (user classes of service 8-12, 26 and 30)
        3.4     Additional capabilities provided by multicast service
 4     Frame relay data transmission service
        4.1     Direct access to a frame relay data transmission service
        4.2     Port access to a frame relay data transmission service
 5     Leased circuit data transmission service
Appendix I – Coding of optional user facilities
       II.1     Introduction
       II.2     Independent operation
       II.3     Minimum relationship
       II.4     Maximum relationship
       II.5     Summary