FWIW I think you will find IO is pretty well qualified and, more to the point, probably one of the most experienced GA pilots on here.
I was flying a Cirrus last week which has a built in telephone. It uses the Iridium network of low orbit satellites rather than a ground based system common to other mobiles.
The system enables you to send SMS anywhere in Europe at any level, receive METARs and TAFs and weather radar. Its certified and, having checked the manual, there is no requirment to turn off the system when flying any approach including an ILS.