If I do say so myself, though, I am doing pretty well on the phone. I do not use any amplification beyond turning up the phone's volume all the way. I do have trouble when people have thick accents or when the connection is bad. Luckily there are always coworkers around who can help me out. And happily enough people have told me my voice is very kind and clear on the phone. I feel lucky in that way, that the phone works for me and with my hearing aids and that I ended up not needing anything special.
However, I have noticed some common pitfalls that people do on the other end that inevitably leads to confusion. As somebody who is relatively new to using a phone regularly, I wanted to write about these and encourage everyone to communicate as clearly as possible. Whether you are deaf or hearing, it is important that communication is clear. It's not just about the other person, it will also help you get what you want faster.
1. Start and end the conversation clearly. Say "hello" and "goodbye" rather than launching into a question or comment and hanging up after you hear a response. "Hello" and "goodbye" are not as much for you as they are for the other person. They are communication markers. (Raise your hand if you now have the Beatles song stuck in your head.)
2. When asked for a name, do not spell it immediately. Say the name first, and if asked, or if the person is having trouble, then spell it. When I am on the phone and ask, for example, for an author's name, it confuses me when people start spouting letters at me. Since I work from context a lot of the time in a sentence, I am expecting words, not single sounds like letters. I inevitably miss the first few letters and they have to spell it anyway.
3. Use the same format the entire way through when listing off numbers. For example, if your phone number is 555-8791, do not say "five-five-five, eighty-seven ninety-one" or any mixture of those. Again, it is about what the other person is expecting. Switching from single numbers to two-digit numbers is confusing and impedes comprehension.
4. If a person is typing and you are listing off an account number or something like that, do not say things like "six, three zeroes, nine..." It may take the person longer to type three zeroes than it does for you to say it, so they will find themselves behind. It is also unexpected by the other person.
5. If you need to speak to someone beside you and you are on the phone, excuse yourself from the phone, put your hand over the mouthpiece, speak to the other person, and then return to the line. This avoids confusion from the other person about who you are speaking to. I've replied to questions that weren't intended for me several times. (The most confusing was "How old are you?")
6. If you are in a crowded place, step outside to continue your conversation or remove yourself to a quieter room.
I think a lot of these are kind of elementary, but it surprises me that so many people ignore them. Since you can't see the other person, I guess they have no idea they are being confusing. Hope this list helped.