There is provided an objective lens for an optical pick-up which is used to recordreproduce data tofrom at least three types of optical discs. A map is scanned into the mobile terminal using the mobile terminal as a scanner. A second data ring is rotatable with the member and includes bit indicators for indicating incremental changes in the angular position of the member. The climbing rail is then displaced in the vertical direction until the lower extension piece is captured within the lower climbing shoe. In one embodiment a common word clock is derived form the set of bit clocks as a whole.