Provided are an optical filter and a stereoscopic display device. The Internet facsimile machine also includes a processor having a communication management recording function for storing a communication record table of the series of electronic mails and outputting the communication record table. An interface in communication with the ports is configurable as to the network layer, or layer 2 and 3, and the physical layer, or layer 1. In an embodiment, the LPC coefficients of the sub-bands are obtained from the correlation coefficients, which are in turn obtained by filtering the auto-regressive extended auto-correlation coefficients of the full band LPCs. Depending on an introduced component characteristic the component’s physical keying structure may be received or prevented depending on the implementation. The coil stops have rollers to facilitate repositioning during loading, and a mid-span step and hand grabs to facilitate climbing over the coil stop by personnel walking along the trough structure.