Most of us use our cell phones everyday for our business calls. We have to keep in mind that the microphones in our cell phones are tiny and they are not nearly as good as those in landlines. We have to work that much harder to be heard and understood while using our cellphones. Speak a bit more slowly than in regular conversation, make sure you are speaking directly into the microphone, speak at a good volume and speak very clearly. Your voice matters, make sure it's heard.
I met a young woman yesterday who is having surgery today on vocal cord nodules and polyps. She teaches cycling classes at several locations and that use of her voice caused the problem with her vocal cords. Her voice sounded very raspy and it hurt my throat just listening to her. I asked her what kind of post-operative speech therapy or voice coaching was recommended by her physician to help her avoid this problem in the future. "None" was her answer. This made me very up