Section 423. (a) Any party in interest may, within twenty days after notice of a workers' compensation judge's adjudication shall have been served upon him, take an appeal to the board on the ground: (1) that the adjudication is not in conformity with the terms of this act, or that the workers' compensation judge committed any other error of law; (2) that the findings of fact and adjudication was unwarranted by sufficient, competent evidence or was procured by fraud, coercion, or other improper conduct of any party in interest. The board may, upon cause shown, extend the time provided in this article for taking such appeal or for the filing of an answer or other pleading.
(b) If a timely appeal is filed by a party in interest pursuant to clause (a), any other party may file a cross-appeal within fourteen days of the date on which the first appeal was filed or within the time prescribed by clause (a), whichever period last expires.
(c) The board shall hear the appeal on the record certified by the workers' compensation judge's office. The board shall affirm the workers' compensation judge adjudication, unless it shall find that the adjudication is not in compliance with section 422(a) and the other provisions of this act.