Client

r = peripheral.wrap("back")
rednet.open("right")

local function send_response(id, response)
    rednet.send(id, response, "response")
    print("A response has been send to: " .. tostring(id))
end

while true do
    id,cmd = rednet.receive("cmd", 20480)
    if id == 4 then
        if cmd == "start" then
            if r.getActive() == true then
                print("The reactor is already active !")
                send_response(4, "The reactor is already active !")
            else
                r.setActive(true)
                print("The reactor has been enabled !")
                send_response(4, "Succesfuly started !")
            end
        else
            if cmd == "stop" then
                if r.getActive() == false then
                    print("The reactor is already inactive !")
                    send_response(4, "The reactor is already inactive !")
                else
                    r.setActive(false)
                    print("The reactor has been disabled !")
                    send_response(4, "Succesfuly stopped !")
                end
            end
        end
    end
    os.sleep(1)
end