A scooter is described herein having control cables for use in guiding the scooter. The functional units are responsive to a data- stream containing data and tokens. First and second lenses therein are spaced apart by a first spacer and a filter therein is spaced from the second lens by a second spacer. Additionally, while not installed in the printer, the pack is covered with the opening and closing ink housing section 211, thereby enabling the printing media to be protected from dusts or the like. Following establishment of pair-wise security between pairs of neighboring network nodes, for a pair of network nodes that are not neighbors, tunnel security is established between the pair of network nodes using tunnel encryption keys derived by the pair of network nodes on an ad hoc basis.