README.md

Serial("port", options)

const escpos = require('escpos');
escpos.SerialPort = require('escpos-serialport');

const serialDeviceOnWindows = new escpos.SerialPort('COM10');
const serialDeviceOnLinux = new escpos.SerialPort('/dev/usb/lp0', {
  baudRate: 14400,
  stopBit: 2
});

Check the serialport package documentation for more options.