A swinging objective retarding immersion lens system and method therefore which provide a low voltage electron beam with high beam current, relatively high spatial resolution, a relative large scan field, and high signal collection efficiency. In this regard, the length of a link over which a first communication device communicates with a second communication device may be determined and Ethernet PHY’s residing in the communication devices may be configured based on the determination. For encryption, plain characters are received, and a key block includes key characters corresponding to the plain characters is accessed. The waveform may be frequency-adapted to maximize formation response and amplitude adapted for gain control.