An apparatus for cleaning a rubbing cloth disposed on an alignment roller includes: a first support member to be disposed parallel to the alignment roller; a second support member to be disposed parallel to the alignment roller and spaced apart from the first support member at a predetermined distance; and a cleaning cloth disposed on and extending between the first and second support members. A certification authority in the digital certificate is compared against a list of registered trusted certification authorities in the registry. A side panel is positioned at a side surface of the mattress. If a deviation is detected, then the user is notified and calibration is failed. When the spring holds the knob away from the cylindrical member, the rod is in a retracted position in which the end of the rod opposite the knob is inside the cylindrical member. Application in dual-core amplifying fibers or lasers or in transmission fibers for local networks.