Connect to serial port via tcp

com2tcp.lua

local uv = require "lluv"
uv.rs232 = require "lluv.rs232"

local sockets = {}

local port = uv.rs232('COM4',{
  baud         = '_9600';
  data_bits    = '_8';
  parity       = 'NONE';
  stop_bits    = '_1';
  flow_control = 'OFF';
  rts          = 'ON';
})

uv.tcp():bind("127.0.0.1", 5555, function(server, err)
  if err then return server:close() end

  server:listen(function(server, err)
    if err then return end

    local cli, err = server:accept()
    if not cli then return server:close() end

    sockets[cli] = true

    cli:start_read(function(cli, err, data)
      if err then
        sockets[cli] = nil
        return cli:close()
      end

      port:write(data)
    end)
  end)
end)

port:open(function(self, err, info, data)
  if err then return self:close() end

  self:start_read(function(self, err, data)
    if err then return self:close() end

    for s in pairs(sockets) do s:write(data) end
  end)
end)

uv.run()