Pin 8 is a diode that duplicates the diode you have across the coil of your relay. Personally I use discrete diodes across any relay I use, and not pin 8.
Pin 7 is an open collector. When pin 7 is activated it shorts to "ground" (pin 15). Pin 15 closes the loop back to where the +12v comes from, that is from the ground side of the 12v relay power supply. Some people have blown the X2 chip using external amps and therefore use the "buffer" relay to switch the amp relay. If you're not sure of your amp and the vagaries of switching voltages and current this is probably a good idea, but it is a belt and suspender solution and it does add some latency to the amp switching. I have 4 amps (ameritron and amp supply) and have never had any trouble using pin 7 to switch without the buffer relay with any of my amps. If I was going to use a buffer I would use something like a FET and not a relay. I looked at the diagram in manual 1.8.0 and it is correct. 73 W9OY ____________________________________________________________________________________ Need a quick answer? Get one in minutes from people who know. Ask your question on www.Answers.yahoo.com _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Homepage: http://www.flex-radio.com/ FlexRadio Knowledge Base: http://kb.flex-radio.com/