Proper phone etiquette in the office includes answering the phone promptly and speaking with a friendly, courteous voice. When answering the phone in the office, use a proper greeting that includes your first name.
Use a moderate speaking volume unless the person on the other end asks for you to speak more loudly. If people stare when you answer a call, it is a sign that your speaking volume is too high. On the other hand, if callers often ask you to repeat information, it means they are finding it difficult to hear you.
Set the office telephone to go directly to voicemail when you walk away from the phone or shortly beforehand, particularly when leaving for lunch hour or a meeting. This prevents the phone from ringing too many times when someone calls and prevents you from becoming involved in a lengthy call shortly before heading out for a meeting.
If it is necessary to put a caller on speakerphone, inform him first. It is poor etiquette to simply have a customer or vendor on speakerphone for everyone to hear without letting him know ahead of time.
If the person you are calling fails to answer the phone, avoid leaving a lengthy voicemail message. Make your message short and succinct. If you leave your telephone number, state it clearly and slowly so that the recipient doesn't have to replay your message multiple times.