DD ENV 12313-4:2000

FOREWORD
INTRODUCTION
1. SCOPE
 1.1 Application
 1.2 Presentation
 1.3 Service Management
 1.4 Transmission
2. NORMATIVE REFERENCES
3. APPLICATION
 3.1 Content of the TMC "travel service"
 3.2 TMC terminal
 3.3 Event-orientated information (ALERT C)
 3.4 Status-orientated information (ALERT Plus)
 3.5 Strategic and tactical information
 3.6 Geographic relevance
 3.7 Transmitted message priority
4. PRESENTATION
 4.1 Event-orientation messages
 4.2 Status-orientated messages
     4.2.1 Message format (varient: 4 bits)
     4.2.2 Collection (11 or 12 bits)
     4.2.3 Statuses (20 or 21 bits)
     4.2.4 Coding mechanism
5. SERVICE MANAGEMENT
 5.1 Introduction
     5.1.1 Pure ALERT C service
     5.1.2 Added value services (ALERT C and ALERT Plus)
 5.2 System messages (32 bits)
     5.2.1 Service layer information
     5.2.2 Network layer information
6. TRANSMISSION
 6.1 System messages
     6.1.1 Type 1A groups
     6.1.2 Type 5A groups
     6.1.3 Type 3A groups
     6.1.4 Type 8A groups
 6.2 Immediate repetition
 6.3 Event-orientated messages (ALERT C)
 6.4 Status-orientated messages (ALERT Plus)
 6.5 Summary

Describes the ALERT PLUS function which is an extension of the ALERT C function. The ALERT C function covers over-oriented information conveyed by the RDS medium, whereas the ALERT PLUS deals with status-oriented information by the same medium. Different status types defined are travel times on road sections, car park occupancy, public transport traffic status and level of service on road section areas. Part of the document is valid for other data transmission media such as AM or Swift broadcasting, digital cellular radio system (GSM) digital audio broadcasting (DAB). The presentation deals with status-orientated messages con tained in three fields: Message Format, Collection Number and Statuses of the locations identified by the collection.