The National Center for Aerospace and Transportation Technologies (NCATT) offers the Aircraft Electronics Technicians certification
Check out the April issue of Avionics News for "Part II: The Shop’s View of NCATT Certification and Hiring Technicians"
“The AET exam is a better measure of Knowledge becasue the candidate must actually know the material in order to pass the exam.” Clay Caessens , Blue Angel Aviation
In the interview he compares the AET exam with the FCC GROL “the FCC exam tests the ability to memorize answers to a govt test.” He only hires AET certified folks or has them test within their first 90 days
As I've said in other posts, certifications are earned by mastery of a body of knowledge and there is something to be said for completing an exam without receiving the question pool in advance.