A height and angle adjustable bed having a rolling base which utilizes a unique pivoting base having castors and a unique support arm assist spring mechanism. The system not only provides a convenient user’s environment, but also enhances the whole performance of speech recognition. Moreover, individual inhalation chambers can be selectively removed from the substance inhalation system without test vapor leaking from any of the inhalation chambers. Each part has first and second longitudinally extending sides. A header of each encoded packet includes a parity packet indicator.