Serial Server or Terminal Servers allows companies to connect with RS485, RS422 or RS232 serial interface to Ethernet LANs. Often products which are available as Terminal Server are simple devices without any security functionality like user authentication and data encryption. Key feature of terminal servers is to enable serial devices to access network server applications, security is not a matter. On the other hand there are many terminal servers which have high advanced security functionality in order to make sure that only qualified personnel can access servers. These servers also make sure that the data that is transmitted over the Internet or LAN is encrypted. Initially Terminal Server was described as devices which can attach to serial RS232 devices like serial printers or “green screen” and transport the traffic through SSH, TELNET, TCP/IP or any other network protocol preferred by the user. Transfer of the traffic is done using an Ethernet connection.
Console Management – Rev SSH, Rev Telnet: users can use SSH or Reverse Telnet to connect to a serial device. Terminal Servers in this application are also called as Console servers. They are called because of the reason that they connect to the console ports, found on the products like PBX’s, servers and routers. They run SSH or Telnet on their PC and then attach to the Terminal Server in order to connect to their decisive serial device.
RAW UDP socket connection: in order to be used with UDP based connection serial data for transport across UDP is converted by Terminal Servers is shared across multiple devices or point to point basis.
RAW TCP socket connection: Terminal Server can start a raw TCP connection. Again this can be on shared basis or point to point devices. User can start TCP sessions from the Terminal Server or from TCP server application.
Back to Back – this is specially designed for wiring problem. For example someone wants to replace a parallel line of modem network with their parallel Ethernet network, or users want to replace RS42, RS485 or RS232 wire and want to run their data over Ethernet without making any changes to the final serial device.