Adding a 6.2.10: Maintaining existing telephony functionality (from clause 13.4.11 of TR 103 708)
Proposal to add:
6.2.10 Maintaining existing telephony functionality
All standard functions of calls with audio (e.g. mute audio, volume, touchtone buttons) shall also function when RTT is included, except where functions are disabled on emergency service calls due to safety concerns or regulations.
NOTE 1: For example, with multiparty RTT, this could include call hold, merging, swapping, and similar functionality.
NOTE 2: Clause 13.3.2 covers "Multiparty call support during emergency service calls.
The results of these proposed changes can be previewed in Annex A of TR 103 708 ( tr_103708v010101p.pdf tr_103708v010101p.docx).