When subpoenaed to give a deposition in a dispute or lawsuit, you are considered to be a witness. Giving a deposition is the same as being in court. Always consult with your lawyer before undergoing a deposition.
During a deposition, answer only questions you understand clearly; put your responses in complete words; never guess at a response; don't argue or lose your temper; pay attention to objections from your lawyer; don't volunteer information; dress appropriately. Always review the record of the deposition carefully.