The benefits of remote access servers and services (RAS)

at first glance, device servers and terminal servers are just devices for connecting to any serial device from your Ethernet network. However, there is one main difference between a device server and a terminal server: the protocols being supported.

While a device server mainly builds a TCP/UDP socket to access the serial ports, a terminal server can do more. This means that any terminal server has the same set of features as a device server—virtual COM port, TCP/UDP socket and serial tunnelling—but a terminal server can also do data logging, routing and remote access.

The LEE9000, LES5000 and LES8000 Terminal Server series enables you to let you dial-in by ISDN or 56K analogue modem services. This is a crucial feature for maintaining the availability of your critical network equipment because you cannot access your serial ports through standard device or terminal server capabilities if your network is down.

Connect any modem to one of these terminal servers or use the LEE9011E with an integrated 56K modem. This gives you two ways of accessing the serial port—through the standard network port or by dial-in.

Just configure a new entry from your Windows® desktop in “Dial- Up Networking” (with notebooks) using your integrated analogue modem to access your serial ports again while your Ethernet or VPN connection is down or not available. For greater security, you can either setup users and passwords, use callback functionalities or combine these terminal servers with your RADIUS servers. With the multiport versions of terminal server series LES5000 and LES8000, you can also build-up modem pools for dial-in or dial-out.