A peace officer must serve in his county or city any subpoena delivered to him by telegraph or teletype for service and must without delay make a return of the service by telegraph or teletype. Any officer making a return of service of a subpoena by telegraph or teletype must certify as to his actions in making the service and file in the telegraph office from which the return is sent a written statement with his signature in the same form as the return on an original subpoena. The service of a teletype subpoena is made by showing the original teletype to the witness personally and informing him of its contents and delivering to him a copy of the teletype.