I did actually have the same problem with TS-480 too. Perhaps it has something to do with the following error messages that I have written down during the last 3 months:
Data Abort at 0x0004e598, called by 0x0000a3bc
RRC was not presponding at all
Data Abort at 0x00046694, called by 0x00046660
Breaks in audio stream
Data Abort at 0x00046938, called by 0x00043e50
Breaks in audio stream
Data Abort at 0x000470f4, called by 0x00046734
Breaks in audio stream, RRC not responding
Any idea what is causing those?
73 de Kari, OH2XX