10 00 10 25 10 60 or 11 30 ghz alternatively the switch means 26 may be a further circuit that is either electronically programmable via commands over the ifl or auto configuring according to an analysis of idu responses to test configurations an exemplary version of the vim 10 contains electronic circuitry 28 comprising a pll voltage controlled oscillator vco 29 frequency reference 22 khz tone generator a voltage variable power supply a simple microprocessor and additional interconnecting monitoring power and or control circuits as shown in fig3 the frequency multiplexed signal elements passing through the ifl 16 to the vim 10 port s 23 carry both power and data signals at direct current dc 30 a standard tone 32 for example 22 khz a standard tone information carrier frequency in the field of the invention a reference frequency 34 for example 10 mhz and l band 36 typically 1 2 ghz the vco 29 and mixer circuits that apply the selected frequency of the vco 29 to the l band 36 may be incorporated into for example a single chip lo integrated circuit for example the u201c satcr 1 u201d integrated circuit by st microelectronics of geneva switzerland of the electronic circuitry 28 by passage through the vim 10 and according to the selected settings of the configuration switches and or switch means 26 the dc.