A data communication apparatus as a device. The rotating arm is pivoted to the frame and switchable between a first position and a second position relative to the frame. The present disclosure also describes systems, methods, and devices for estimating spectral contributions in light or color measurements and accounting for field of view errors to obtain a refined estimate. Upon rotation of the belt by the motor assembly, the at least one actuator causes the at least one pickup arm to lift a portion of a page while a subset of the plurality of fingers hold the bound pages in an open condition and turn the lifted page. These methods are inefficient in some applications.