import socket
 import struct

 class eth8020:
     def __init__(self, hostname, port=17494):
         self.s = socket.create_connection((hostname, int(port)))

     def execute(self, request):
         self.s.send(request)
         response = self.s.recv(10)
         return struct.unpack('B', response)[0]

     def set(self, index, value):
         if value:
             return self.activate(index)
         return self.deactivate(index)

     def activate(self, index, duration=0):
         request = struct.pack('BBB', 0x20, index, duration)
         return self.execute(request)

     def deactivate(self, index, duration=0):
         request = struct.pack('BBB', 0x21, index, duration)
         return self.execute(request)

 if __name__ == '__main__':
     import argparse, sys
     p = argparse.ArgumentParser(description="Command-line utility for controlling the Antratek ETH8020.")
     p.add_argument('ip_address')
     p.add_argument('relay', type=int, help="relay index 1..20")
     p.add_argument('action', type=int, help="1=activate, 0=deactivate.")
     p.add_argument('-q', dest='quiet', action='store_true', help="Do not print to stdout.")
     args = p.parse_args()

     e = eth8020(args.ip_address)
     r = e.set(args.relay, args.action)
     if not args.quiet:
         print('success' if not r else 'failed')
     sys.exit(r)