The Telnet driver can act as a Telnet Client or Server. As a Server it supports the following options:

• Telnet sessions initiated by standard Telnet clients, allowing users to access a Command Line Interface on the FieldServer.
• Serial Port Capture on the FieldServer to allow user interaction with serial devices via Telnet, either through the Telnet server user interface, or by pre-configured auto-connect.
• Pre-configured binary connection from Telnet to Serial Port, i.e. as a Remote Serial Port Server which can be used by PC-based serial port redirectors. Present support is for "raw TCP" mode; RFC2217 port control functionality will be implemented in future.
• Any serial protocol supported by the FieldServer may be run in a Serial-over-Ethernet mode, e.g. TL1.

As a Telnet Client the FieldServer can connect to another Telnet Server, for example to provide seamless serial-to-serial connectivity between two FieldServers over Ethernet.

Ethernet
Client or Server

1. For each Telnet Client or Server connection on a FieldServer a different IP Address and IP Port number may be specified. It is thus possible to map multiple ports on a single FieldServer to multiple TCP connections.
2. In Text Mode options exist to control echoing of typed characters, as well as the rendition of carriage return, linefeed and tab characters.
3. In Text Mode the Telnet Server supports user authentication through a username and password configured on the FieldServer.
4. A connection timeout may be configured to control recovery from lost connections through device or cable failures.