I use a choke chain, but if you don't have one, make a loop out of her dog leash handle and slip that over her neck.

Put it on when the phone rings - maybe practice with having somebody call you, so you're not missing an important call a few times till she starts to get it. Yank the leash and say NO! at every bark. Make her sit. No praise, no petting, no affection.

She needs to not even think about barking. And by now, you know her well enough to see it in her body language that she is getting tense, going to start yapping. I can tell when my dogs are about to open their mouths.

Get her then - yank, NO! Sit. Shhh. And talk on the phone until she starts up again. It takes repetition and consistancy. But that's the same technique I use on all the bad behaviors, yapping at the wrong times, taking the baby's toys, or trying to get out the door when I need them in the house. They *get* yank and No. And they seem to relax and not act up as fast from a sit position.

Good luck with her.