an electrical signal regenerator including an equalizer and a clock data recovery circuit is provided . the clock data recovery circuit is selected when an input signal of a higher bitrate multiplex level is detected , but the clock data recovery circuit is bypassed when an input signal of a lower bitrate multiplex signal is detected . the electrical signal regenerator can be used in an optical switch processing signals of the new otn according to itu - t g . 709 , in which optical signals undergo optical to electrical conversion and are fed to an electrical space switching matrix including a plurality of the switch modules electrically interconnected by means of internal electrical signal paths such as a backplane or electrical cables . the electrical signal regenerator can be coupled to each input of a switching module to check internal cabling of the switching matrix .