console.py

#!/usr/bin/python

import sys
import usb.core
from time import sleep
from threading import Thread,Lock

bmRequestTypeIn = usb.util.build_request_type(usb.util.CTRL_IN, usb.util.CTRL_TYPE_VENDOR, usb.util.CTRL_RECIPIENT_INTERFACE)
bmRequestTypeOut = usb.util.build_request_type(usb.util.CTRL_OUT, usb.util.CTRL_TYPE_VENDOR, usb.util.CTRL_RECIPIENT_INTERFACE)

class Badge:
    def __init__(self, device):
        self.dev = device
        self.lock = Lock()

    def send(self, data):
        if len(data) >= 31:
            data = data[:30]
        self.lock.acquire()
        self.dev.ctrl_transfer(bmRequestTypeOut, 0x61, 0, 0, data)
        self.lock.release()

    def recv(self):
        self.lock.acquire()
        ret = self.dev.ctrl_transfer(bmRequestTypeIn, 0x60, 0, 0, 16)
        self.lock.release()
        raw = ''.join(chr(x) for x in ret)
        if len(raw) > 0:
            return raw
        else:
            return None


class OutputMonitor(Thread):
    def __init__(self, badge, manager):
        Thread.__init__(self)
        self.badge = badge
        self.manager = manager
        self.cancel = False

    def run(self):
        while not self.cancel:
            try:
                data = self.badge.recv()
                if data is not None:
                    sys.stdout.write(data)
                    sys.stdout.flush()
                sleep(0.01)
            except Exception as e:
                print("You got an exception: %s" % e)
                self.manager.exit()

class InputMonitor(Thread):
    def __init__(self, badge, manager):
        Thread.__init__(self)
        self.badge = badge
        self.manager = manager
        self.cancel = False

    def run(self):
        while not self.cancel:
            line = sys.stdin.readline()
            if line == 'exit\n':
                self.manager.exit()
                break
            if len(line) > 0:
                self.badge.send(line)

class Console:
    def run(self):
        # find device
        print('*** Ndh2k14 serial console ***')
        print(' - waiting for device ...')

        device = None
        while device is None:
            device = usb.core.find(idProduct=0x05dc, idVendor=0x16c0)
        print(' - device detected, spawning console')

        self.badge = Badge(device)
        self.outputmon = OutputMonitor(self.badge, self)
        self.inputmon = InputMonitor(self.badge, self)
        self.outputmon.start()
        self.inputmon.start()

    def exit(self):
        self.inputmon.cancel = True
        self.outputmon.cancel = True

c = Console()
c.run()