Do businesses need to have a qualified interpreter on hand in order to communicate with a person who is deaf?

Generally no, not if employees are able to communicate by using pen and notepad and it is effective.  However, in situations where the exchange of information is over a long duration or the information being exchanged is complex it may be necessary for the business to provide a qualified interpreter. A business should discuss with the person with the disability to determine which auxiliary aid or service will result in effective communication.