startup

local modem = peripheral.wrap("back")
modem.open(10)
modem.transmit(10,10,"init")


  event, side,frequency, replyFrequency, message, distance = os.pullEvent("modem_message")

  if (message == true) then
  print("Door is open")
  print("Press C to close it")

  end
  if (message == false) then
  print("Door is closed")
  print("Press O to open it")

  end