Have SPA514G phones using firmware version 7.5.3. Line ID Mapping is set to Vertical First. First call comes into phone and rings 1st button (Call Appearance). Second call rings behind the 1st button instead of ringing 2nd button on set. It appears that something else is over-riding the Line_ID_Mapping option in the config. Not seeing this issue on SPA504G using same config but on different firmware (7.4.9c) I can alter Line_ID_Mapping to Vertical First or Horizontal and incoming calls appear as they should depending on setting. looks like this may have been an issue before in version 7.4.2(?)