(a) In conducting an investigation, hearing, or other proceeding, the chairman or any member of the commission, or a special master when a hearing is being conducted before a special master, may, on his own motion, or on request of appropriate commission staff, the examiner, or the judge, issue a subpoena for attendance of any witness or witnesses who may be represented to reside within the State of Texas.

(b) The style of the subpoena shall be "The State of Texas." It shall state the style of the proceeding, that the proceeding is pending before the commission, the time and place at which the witness is required to appear, and the person or official body at whose instance the witness is summoned. It shall be signed by the chairman or some other member of the commission, or by the special master when a hearing is before the special master, and the date of its issuance shall be noted thereon. It shall be addressed to any peace officer of the State of Texas or to a person designated by the chairman to make service thereof.

(c) A subpoena may also command the person to whom it is directed to produce the books, papers, documents or tangible things designated therein.

(d) Subpoenas may be executed and returned at any time, and shall be served by delivering a copy of such subpoena to the witness; the person serving the subpoena shall make due return thereof, showing the time and manner of service, or service thereof may be accepted by any witness by a written memorandum, signed by such witness, attached to the subpoena.