A friend of mine works as a PBX operator in a large hotel in San Francisco. If you want to land a job as a PBX operator, you must have a positive customer service attitude. She told me that a very important responsibility is to help the customer in any way possible.
You need to have a nice sounding voice and be polite. Learn to be calm - the job is sometimes very stressful.
One very good advantage to having this job is that you get to know about the various departments in the hotel. You may want to move into another department someday!