Embodiments of the present invention exploit the existing capabilities of the Ethernet Passive Optical Network MAC layer, designed for fiber optics communications, to provide a low cost MAC layer with upper layer connectivity over a hybrid fiber coaxial network. In one embodiment, the image capture accelerator includes accelerator circuitry including a pre-processing engine and a compression engine. The level adjustment mechanism including level adjustable projections adapted to project from the bars against a support structure, and provided with a surface which extends in a longitudinal direction of the bars, as seen in the use of the system, and with engagement adapted for engagement with recess. An actuator is inserted into the hollow shaft to be movable through the hollow shaft.