The issuance of subpoenas to compel the attendance of witnesses and the production of books, papers, correspondence, memoranda and other records and documents, may be obtained on application to the Board, referee, or at any local employment office. In no case may a subpoena be issued to require the appearance of a witness before the tribunal unless his residence is within 100 miles of the place fixed for his appearance.
34 Pa. Code § 101.31