Modular plugs and jacks connect data signal transmission cables to computer components are provided with cross-talk reducing members surrounding or between parallel or near parallel sections of conductors in the plugs and jacks. The manifold is connected to a source of liquid and the apparatus includes directional control switches for reversing the direction of the drive wheel. Each Uniform Device Descriptor file characterizes a set of attributes associated with its corresponding digital device. By selecting different periodic arrangements, different, non-overlapping wavelength ranges can be selected and the laser can be tuned over a broad range of wavelengths.