How about sender call + 9 or group ?
How about allow multiple TDMS frame's for data, several radios at same whit own slot ?
Flexibility, data/voice could have headers, so multiple codec could be in use,..
Could there be frame id's so for example instead voice data can be sended GPS or message or data,.. and next time you have slot againg continue whit voice ??
This could be multi codec ?