A container which includes a container shell defining an interior therein and having an opening for accessing the interior. The method includes defining a subarea of the image having parts of a number of the scan lines, extracting the subarea, generating a set of auxiliary code blocks having an auxiliary differentially encoded parameter based on the first differentially encoded parameter of a first code block of a first current scan line in the subarea, and associating the auxiliary code blocks with the subarea. The first adapter transmits the data by electromagnetic coupling to a first transceiver placed on the first block. The linking piece can also disengage from the frame arms to allow the frame arms to be folded up. In order to access advanced conferencing features, the conferencing system employs an enhanced SIP signaling technique including a conferencing Application Programming Interface implemented by incorporating Extensible Mark-up Language messages in the bodies of respective SIP requestresponse messages. Each tread assembly is disposed adjacent to at least one of another of the tread assemblies and includes a tread plate and a first and a second telescoping support member attached to a rear surface of the tread plate.