The optical transceiver of the present invention is one type of the pluggable transceiver that is inserted intoextracted from the cage in the host system. These are arranged in the order of a first lens group that has positive refractive power and a second lens group that has negative refractive power, as seen from the side having the longer conjugate distance, wherein a first lens of the lenses of the second lens group, as seen from the side having the longer conjugate distance, has positive refractive power. A head on each linear element, positioned in a central aperture of a main body of the coupler retains the linear element axially in the coupler. For a different implement, one single-acting hydraulic actuator can be connected to one connector port and another single-acting hydraulic actuator can be connected to the other port of the same connector. One embodiment includes a method for monitoring hands-free accessibility of media items for play at a vehicle.