The invention is a hospital bed with inflatable bladders and a system to inflate and deflate the bladders. Included is a controller area network (CAN) that communicates with the pressure control system. Claim 1 detailed how the CAN has a number of modules and a serial bus connecting those modules such that the modules are in communication with each other. Dixon, the inventor, has a B.S.E.E. and has practical experience with electronic communications. The examiner found that one skilled in the art would possess scientific and engineering for a complex hospital bed system and would also possess knowledge of medical systems and hospital communication networks. The inter partes examination went against P and P appealed. In part, P claims that the examiner did not define the proper level of a person of ordinary skill in the art. Under the Graham test, the underlying factual inquiries are: (1) the scope and content of the prior art, (2) the differences between the prior art and the claims at issue, (3) the level of ordinary skill in the pertinent art, and (4) secondary considerations of nonobviousness. P contends on appeal that a person of ordinary skill would require more information than provided in the secondary references and their own knowledge to implement CAN. P claims that the Examiner did not identify an articulable standard for the level of ordinary skill in the art.