Question

The telephone rang inside, startlingly, and as Daisy shook her head decisively at Tom the subject of the stables, in fact all subjects, vanished into air. Among the broken fragments of the last five minutes at table I remember the candles being lit again, pointlessly, and I was conscious of wanting to look squarely at every one, and yet to avoid all eyes. I couldn’t guess what Daisy and Tom were thinking, but I doubt if even Miss Baker, who seemed to have mastered a certain hardy skepticism, was able utterly to put this fifth guest’s shrill metallic urgency out of mind. To a certain temperament the situation might have seemed intriguing—my own instinct was to telephone immediately for the police. The phone calls that Tom receives during the dinner are an indicator that

Answer 1

It's an indicator that he and Daisy are not a happily married couple.
the telephone in this situation represents Tom's live outside the one With Daisy (Tom constantly cheat on Daisy in their relationship)
Daisy had a tell of the situation but never really do anything about it and everytime the phone rang, Daisy know that Tom can't wait to get away from her