[SOLVED] ON/OFF value to Dimmer type?

Setup, Configuration and Use Items & Sitemaps
2

No, in general Dimmer Item supports ON and OFF command, but the linked channel has to support ON/OFF command, too. You could use a simple rule:

rule "send number in addition of ON/OFF"
when
    Item myDimmerItem received command
then
    switch (receivedCommand) {
        case ON       : myDimmerItem.sendCommand(100)
        case OFF      : myDimmerItem.sendCommand(0)
        case INCREASE : myDimmerItem.sendCommand((myDimmerItem.state as Number) + 5)
        case DECREASE : myDimmerItem.sendCommand((myDimmerItem.state as Number) - 5)
    }
end

This will “translate” the commands ON, OFF, INCREASE and DECREASE to a set level command. In fact, INCREASE and DECREASE are often unused (but you will need them for classic UI)