When in-band tones/announcements not associated with a call state change are to be provided by the network before reaching the Active state, a PROGRESS message is returned simultaneously with the application of the in-band tone/announcement. The PROGRESS message contains the progress indicator No. 8, in-band information or appropriate pattern is now available.
When tones/announcements have to be provided together with a call state change, then the appropriate message [e.g.for ALERTING, DISCONNECT, etc., (see clause 3)] with progress indicator No. 8, in-band information or appropriate pattern is now available is sent simultaneously with the application of the in-band tone/announcement.
NOTES
1 When the network provides ITU-T standardized telecommunications services, the service requirement for provision of in-band tones/announcements is as indicated in the I.200-series Recommendations.
2 When the PROGRESS message is used, the user may initiate call clearing as a result of the applied in-band tone/announcement, according to the procedures specified in 5.3.3.