Energy-O-Mat

A toll cable: the owner's energy enters through any side but the front and leaves through the front only while there is credit. The owner puts the price in “Wants” (an iridium coin, for example) and sets with the buttons how many EU each payment buys (4000 at first). The customer puts the payment below; it is stored in an adjacent chest or Personal Safe of the owner. With no price or nowhere to store the payment, energy passes for free. It sends LV packets (32 EU), up to 512 EU/t, and gives a redstone signal while energy passes. It cannot be broken; the owner removes it with a wrench.