A data processing system includes a decoder circuit, syndrome calculation circuit and hash calculation circuit. The apparatus includes, inter alia, a base member which is positioned proximate to the surgical site, a support arm extending proximally from the base member, an arcuate guide member and a drill assembly. The folded end portions of both contact pieces are buried within the combining block and the remaining parts of both contact pieces are projected from the combining block. A third improvement concerns a logic for controlling the engagement and disengagement of a pair of stabilizer bar assemblies. The second data have a packet data format. The method further includes dispensing at least one PIN corresponding to the desired prepaid service from the client terminal.