User manual Version 1.1
SE5408/SE5416 Multi-port
Serial Server
Copyright © 2010 ATOP Technologies, Inc.
All rights reserved. Designed in Taiwan
- 17 -
Tunneling Mode (Client-Server Pair)
Tunneling Mode is used for a serial device to “talk” to another serial device through an Ethernet (TCP/IP)
connection which is provided by SE5408/SE5416 Multi-Port Serial Server. This mode is particularly useful
when needed to connect two serial devices that are far away, e.g. more than 15 meters for RS232 serial
connection. Only one pair of serial devices is allowed to make a connection in Tunneling Mode. To form
the “tunnel”, one serial device must be configured as a server and the other must be configured as a
client.
As shown in Fig 10, to configure a tunnel connection, first assign a TCP server with “Maximum
Connection set to “1”. The “Client” IP address is 10.0.50.101 and the “Destination IP” must be the TCP
server IP address 10.0.55.201. Finally, make the “Destination Port” the same as the local port (or listening)
of the TCP server which is 5660 in this example.
Fig 10. In Tunneling Mode, one device serving as a TCP server and the other as a TCP client
In Fig 11, an HMI (a serial device) communicates with a PLC through a “TCP Tunnel”. The local (listening)
port number of the server is 4660. The lower SE5416 device that is connected to a PLC acts as a TCP
client, so its destination port must be the listening port of the TCP server which is 4700 in this example.
Fig 11. HMI and PLC “Tunneling” over a LAN using device server in Tunneling Mode
