At 6/3/2010 07:16, you wrote:
>Hi Scott, > >Many controllers have pullup resistors on their COR inputs so that they >can be driven from open collector or relay contact COR outputs. With that >arrangement, if the controller is configured for active high and the COR >line is disconnected, the controller will think the receiver is active. > >The best arrangement is the one that works for you. There aren't any >standards -- except perhaps in industrial control, where there are fewer >active low circuits due to the possibility of activating a circuit due to >a pinched wire. I use active high on the COS & active low on the CTCSS. That way any failure that occurs equally to both lines will not key the TX. Bob NO6B
