TELNET client function

Specifications of the TELNET client function

       +------------------+    +------------------+
       |  Yamaha router   |    |  TCP/IP devices  |
       |                  |    |                  |
       |  TELNET client   | -> |  TELNET server   |
       +--------+---------+    +--------+---------+
                |                       |

Communication parameter

Item Value
Connection protocol TCP
Destination port number 23
The number of concurrent connection 1

The user can designate the destination port number by 'telnet' command parameter.

Restriction of TELNET client function

  • Restriction by the security class
    The TELNET client function is disabled by default settings.
  • Restriction by the privilege level
    Only administrator level user can use the TELNET client function.
    The number of concurrent connection is 1.

Automatic mode type selection by connection port number

  • Character mode / Line mode
Destination port number Mode
23 Character
other Line

Negotiating TELNET options

Destination port number Negotiating TELNET options
23 Enable
other Disable

Mode description

  • Character mode
    Each character is sent to / received from the TELNET server as soon as possible without any modification.
  • Line mode
    The input characters from the console are stored by Yamaha router and user can edit the line until the 'Enable' key is pressed.
    After the 'Enable' key, the line is sent to the TELNET server. The EOL (End Of Line) of the line is fixed to CRLF (2byte, 0x0d 0x0a) even if the console uses another EOL.

TELNET command format


telnet host [ port [ mode [ negotiation [ abort ] ] ] ]


host: Telnet server

  • IP address
  • Host name

port: Destination port number to connect

  • Port number
  • The mnemonic assigned to specified port number
  • [Initial value]: 23

mode: Operation mode

  • character: Character mode
  • line: Line mode
  • auto: According to the 'port' parameter.
  • [Initial value]: auto

negotiation: Negotiate the telnet option or not

  • on: The negotiation is enabled.
  • off: The negotiation is disabled.
  • auto: According to the 'port' parameter.
  • [Initial value]: auto

abort: Abort key to forcibly disconnection

  • The abort-key code (ASCII-character codes with decimal numbers)
  • [Initial value]: 29(^])

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