(1) Whenever a person has entered upon a term of imprisonment in a penal, correctional, or juvenile rehabilitation institution of this state, and whenever during the continuance of the term of imprisonment there is pending in this state any untried indictment, information, or complaint against the person, he or she shall be brought to trial within 120 days after he or she shall have caused to be delivered to the prosecuting attorney and the court in which the indictment, information, or complaint is pending written notice of the place of his or her imprisonment and his or her request for a final disposition to be made of the indictment, information, or complaint. The following time periods shall be excluded from the 120-day calculation:

(a) Arraignment, pretrial proceedings, trial, and sentencing on an unrelated charge in a different county than the court where the charge is pending;

(b) Proceedings related to competency to stand trial on the pending charge, from the entry of an evaluation order to the entry of a court order finding the person competent to proceed; and

(c) Time during which the person is detained in a federal jail or prison and subject to conditions of release not imposed by the state of Washington.

(2) The superintendent or the superintendent's designee who provides the certificate under subsection (4) of this section shall inform any prosecuting attorney or court requesting transportation of the person to resolve an untried indictment, information, or complaint of the person's current location and availability for trial. If the person is unavailable for transportation due to court proceedings in another county, the superintendent shall inform the prosecuting attorney or court when the person becomes available for transportation and provide a new certificate containing the information under subsection (4) of this section.

(3) For good cause shown in open court, with the person or his or her counsel having the right to be present, the court having jurisdiction of the matter may grant any necessary or reasonable continuance.

(4) The request of the person shall be accompanied by a certificate of the superintendent or the superintendent's designee having custody of the person, stating the term of commitment under which the person is being held, the time already served, the time remaining to be served on the sentence, the amount of good time earned, the earned release date of the person, and any decisions of the indeterminate sentence review board relating to the person.

(5) The written notice and request for final disposition referred to in subsection (1) of this section shall be given or sent by the person to the superintendent or the superintendent's designee having custody of him or her, who shall promptly forward it together with the certificate to the appropriate prosecuting attorney and superior, district, municipal, or juvenile court by certified mail, return receipt requested.

(6) The superintendent or the superintendent's designee having custody of the person shall promptly inform him or her in writing of the source and contents of any untried indictment, information, or complaint against him or her concerning which the superintendent or the superintendent's designee has knowledge and of his or her right to make a request for final disposition thereof.

(7) Escape from custody by the person subsequent to his or her execution of the request for final disposition referred to in subsection (1) of this section shall void the request.