CONTENTS

 1     Scope 
 2     References 
 3     Definitions  
 4     Abbreviations   
 5     Introduction      
        5.1     Overview of Text over IP  
        5.2     ToIP system architecture    
        5.3     Compliance requirements   
        5.4     Relationship with other V.15x Recommendations    
 6     Text telephone-over-IP functions 
 7     Connection and network scenarios           
        7.1     Service and performance requirements for ToIP     
        7.2     Audio and text functionality
 8     Transport methods           
        8.1     Audio mode          
        8.2     VBD mode
        8.3     Text relay mode     
        8.4     Switching between transport modes           
 9     ToIP operational modes   
10     Text Relay PHY layer operation  
11     IP transport for text relay
       11.1     Single and dual port operation of text relay
       11.2     Text relay throughput        
12     Support of DTMF in ToIP          
13     Transition out of text relay           
14     T.140 encoding of text relay        
       14.1     Character set support       
       14.2     TIA-825A and T.50 encoding requirements          
15     Gateway-to-gateway protocol definitions and procedures
       15.1     Gateway capability and call set-up messages         
       15.2     Gateway call discrimination messages        
16     Start-up mode of operation         
       16.1     Inter-relationship with V.150.1      
       16.2     Inter-relation with V.152   
17     Voiceband data modem interworking requirements          
18     Facsimile interworking requirements        
19     Call set-up procedures    
20     Call discrimination procedures     
       20.1     V.8 bis processing
       20.2     V.8 CI/XCI processing     
       20.3     Call discrimination overview          
       20.4     Call discrimination SDL diagrams  
       20.5     Visual flow control
Annex A – Procedures for the optional support of SPRT protocol    
        A.1     Overview  
        A.2     SDP negotiation    
        A.3     H.245 negotiation 
Annex B – Definition of capabilities for use within H.245-based systems    
Annex C – SDP description of sessions supporting V.151    
Annex D – Interworking IP text devices with V.151 gateways    
        D.1     Introduction          
        D.2     Exchanging capabilities and opening media streams
        D.3     State transition and text handling    
Annex E – Payload format and signaling syntax for real-time  text transported within an audio stream    
        E.1     Overview  
        E.2     Payload format      
        E.3     Use of redundancy
Appendix I – Background to PSTN text telephony    
Appendix II – ToIP call discrimination call flows    
       II.1     Scope     
       II.2     Scenarios for call discrimination flows         
       II.3     Scenarios with SSE protocol being used     
       II.4     Scenarios with payload type switching being used   
Appendix III – The use of [IETF RFC 2198] in [ITU-T V.151]    
Appendix IV – Text buffering and transmission    
Appendix V – Probing sequence    
Bibliography