Difference between revisions of "Cyclades Terminal Server"
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== What is a Terminal Server? == | == What is a Terminal Server? == | ||
| − | A terminal server provides TCP/IP connectivity to RS-232 serial ports. Effectively, it lets you communicate with a serial port from anywhere on the Internet. | + | A terminal server provides TCP/IP connectivity to [http://en.wikipedia.org/wiki/RS-232 RS-232] serial ports. Effectively, it lets you communicate with a serial port from anywhere on the Internet. |
While this can be used for access to serial devices such as measurement tools and printers, or to enable a dedicated terminal to communicate with a network host, the terminal server in the EHL is used in a different way: it permits remote access to the serial console ports on computers within the EHL. | While this can be used for access to serial devices such as measurement tools and printers, or to enable a dedicated terminal to communicate with a network host, the terminal server in the EHL is used in a different way: it permits remote access to the serial console ports on computers within the EHL. | ||
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Most system firmware, boot software, and Linux kernels provide a console user interface. Only after the system is fully booted do network services become active. | Most system firmware, boot software, and Linux kernels provide a console user interface. Only after the system is fully booted do network services become active. | ||
| − | On a PC, the console is often provided through a local video connection. On hyperscale system, it may be provided by an IPMI serial-over-LAN (SOL) connection. On a development board, it is usually provided by an RS-232 (or RS-485 or TTL) serial connection. | + | On a PC, the console is often provided through a local video connection. On hyperscale system, it may be provided by an IPMI serial-over-LAN (SOL) connection. On a development board, it is usually provided by an RS-232 (or RS-485 or TTL) serial connection, and it is for this type of connection that a terminal server is used. |
== The EHL Terminal Server == | == The EHL Terminal Server == | ||
Revision as of 20:46, 13 November 2014
The EHL is equipped with a Avocent Cyclades 32-port terminal server for access to the console port on specific development systems.
Contents
What is a Terminal Server?
A terminal server provides TCP/IP connectivity to RS-232 serial ports. Effectively, it lets you communicate with a serial port from anywhere on the Internet.
While this can be used for access to serial devices such as measurement tools and printers, or to enable a dedicated terminal to communicate with a network host, the terminal server in the EHL is used in a different way: it permits remote access to the serial console ports on computers within the EHL.
Most system firmware, boot software, and Linux kernels provide a console user interface. Only after the system is fully booted do network services become active.
On a PC, the console is often provided through a local video connection. On hyperscale system, it may be provided by an IPMI serial-over-LAN (SOL) connection. On a development board, it is usually provided by an RS-232 (or RS-485 or TTL) serial connection, and it is for this type of connection that a terminal server is used.
The EHL Terminal Server
The EHL terminal server is accessed through iraq.proximity.on.ca and has the local hostname "terminal".
Web Access
Web access to the terminal server permits you to configure a port for access, including the communication details (speed, word length, parity) and port security. Access http://terminal/ from Iraq.
The web interface also provides a Java-applet-based client for port access, but it is usually better to ssh directly to the port (below).
SSH Access
SSH access is the easiest and best way to access console ports connected to the terminal server.
SSH to the terminal server using the user ID username:port where username is your username on the terminal server and port is 7000 + serial port number. For example, to connect to serial port 3 with the Cyclades username "ostep", issue this command on Iraq:
ssh ostep:7003@terminal
Wiring
The Cyclades terminal server is connected to device serial ports using RJ-45 straight-through (not crossover) cables. These are connected directly to the Cyclades unit on one end, and to adapters (RJ-45f to DB-9f or RJ-45f to DB-25f) on the other end.
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Ethernet and serial connections in the EHL both use RJ-45 cables. Never connect the two, because they use incompatible voltage levels and signaling. RED cables must be used for serial connections and for nothing else; only non-RED cables shall be used for ethernet connections.
