server

term.clear()
term.setCursorPos(1, 1)

textutils.slowPrint("Starting alert server...")

local modem = peripheral.wrap("back")
local password = "pass123"

modem.open(3000)
modem.open(3001)

while true do
  local event, modemSide, senderChannel,
    replyChannel, message, senderDistance = os.pullEvent("modem_message")
  if message == password then
    if senderChannel == 3000 then
      redstone.setOutput("bottom", true)
    end
    if senderChannel == 3001 then
      redstone.setOutput("bottom", false)
    end
  end
end