Tex. Code of Criminal Procedure § 5

An order to a witness and to a person having custody of the witness shall provide for the return of the witness at the conclusion of his testimony, proper safeguards on his custody, and proper financial reimbursement or prepayment by the requesting jurisdiction for all expenses incurred in the production and return of the witness. The order may prescribe any other condition the judge thinks proper or necessary. The judge shall not require prepayment of expenses if the judge directs and requires the requesting jurisdiction to accept custody of the witness at the Texas penal institution in which the witness is confined and to deliver the witness back to the same or another Texas penal institution at the conclusion of his testimony. An order does not become effective until the judge of the state requesting the witness enters an order directing compliance with the conditions prescribed.