SECTION 7 - SUPPLEMENTARY SERVICES

Recommendation Q.80

          INTRODUCTION TO STAGE 2 SERVICE DESCRIPTIONS
                   FOR SUPPLEMENTARY SERVICES
                                
                            Contents
                                

1.     Introduction

2.     Cross-references

3.     Relationships among supplementary services

Annex I - Cross-reference list of Stage 1 and Stage 2 Recommendations on
          supplementary services 
                                   *
                                    
                                *     *
                                    
SECTION 7 - SUPPLEMENTARY SERVICES

Recommendation Q.80

              INTRODUCTION TO STAGE 2 SERVICE DESCRIPTIONS
                       FOR SUPPLEMENTARY SERVICES


1.     Introduction

       The purpose of this Recommendation is to provide an introduction  to  the
Stage  2   service   descriptions   for   supplementary   services,   given   in
Recommendations Q.81-87.

2.     Cross-references

       The work in Recommendations Q.81-87 is  based  on  the  Stage  1  service
descriptions given in the I.251-2570-Series Recommendations (see Annex I). They are 
coordinated with the Stage 2 service  description  for  basic  calls,  given  in
Recommendation Q.71, and were developed according to the  methodology  given  in
Recommendation Q.65.

3.     Relationships among supplementary services

3.1    Call Diversion Services

       Recommendation I.252,  2-5, defines a  set  of  supplementary  services
called "Call Diversion Services". This  set  consists  of  the  Call  Forwarding
supplementary services and the Call Deflection supplementary service. This section 
describes how these services relate to each other and describes the different network 
routing techniques which may be used to provide these services. It begins with the 
latter topic.

















                                    Annex 1
                                        
                         (to draft Recommendation Q.80)
                                        
                  Cross-reference list of Stage 1 and Stage 2
                  Recommendations on supplementary services  1
                                        

Stage 2                                    Based on Stage 1 given in:

Q.80 - Introduction to Stage 2 Service                     
       Descriptions for Supplementary
       Services      
Q.81 - Number Identification Supplementary            I.251
       Services

 1    Direct Dialling In                      I.251,  1
( 2)  Multiple Subscriber Number                     I.251,  2
 3    CLIP                                           I.251,  3
 4    CLIR                                           I.251,  4
 5    COLP                                           I.251,  5
 6    COLR                                           I.251,  6
( 7)  Malicious Call ID                              (I.251,  7)
( 8)  Sub-Addressing                                 (I.251,  8)

Q.82 - Call Offering Supplementary Services           I.252

( 1)  Call Transfer                                  I.252,  1
 2    Call Forwarding Busy                           I.252,  2
 3    Call Forwarding No Reply                       I.252,  3
 4    Call Forwarding Unconditional                  I.252,  4
( 5)  Call Deflection                                (I.252,  5)
 6    Line Hunting                                   I.252,  6

Q.83 - Call Completion Supplementary Services         I.253

 1    Call Waiting                                   I.253,  1
 2    Call Hold                                      I.253,  2
( 3)  CCBS                                           (I.253, .3)

Q.84 - Multi-Party Supplementary Services             I.254

( 1)  Conference Calling                             I.254,  1
( 2)  Three-Party                                    I.254,  2

Q.85 - "Community of Interest" Supplementary          I.255
       Services

 1    Closed User Group                              I.255,  1
( 2)  ISDN Networking Services                       (I.255,  2)
       Private Numbering Plan

Q.86 - Charging Supplementary Services                I.256

 1    Credit Card Calling                            I.256,  1
 2    Advice of Charge                               I.256,  2
( 3)  Reverse Charging                               (I.256,  3)







Q.87 - Additional Information Transfer                I.257
       Supplementary Services

 1    User-to-User Signalling                        I.257,  1


 Parentheses "( )" around a  of a Recommendation number implies
    that the  may not appear in the 1988 CCITT Recommendations.