Where I've played in New England the general rule seems to be that if you are in a hand you cannot be using your phone, and if you want to talk on it you need to get up from the table. It seems to work pretty smoothly, except for one morning tournament I was playing at Mohegan Sun a year or two ago.
There was a young man, probably in his early thirties, who was constantly on his phone. He was constantly warned by the dealer, and constantly he ignored it. Finally one of the floor people came over and got him to not use the phone while he was in a hand. Of course he wasn't about to quit there so he turned slightly to the side and put his feet up on the empty chair next to him his.
That caused another controversy between him, the dealer, and the floor people. It went on for about fifteen minutes until he finally relented and played sans phone with his feet flat on the floor. I thought that I might be seeing a recreation of a scene in the movie
Casino but, at least on that day, it wasn't in the cards for him.