VMS Help TCPIP Services, Programming Interfaces, Sockets API, $QIO, TELNET Port Driver QIO Interface  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The TELNET port driver (TNDRIVER) provides terminal session
    support for TCP stream connections using the RAW, NVT, RLOGIN,
    and TELNET protocols. Either a remote device or an application
    can be present at the remote endpoint of the connection.
    A user program can manage a TELNET connection with the standard
    OpenVMS $QIO system service by using the IO$_TTY_PORT and IO$_
    TTY_PORT_BUFIO I/O function codes. This section describes these
    I/O function codes and their associated arguments.

  Additional Information (explode) :

• Interface Definition
• Passing Parameters to the TELNET Port Driver