VMS Help TCPIP Services, Programming Interfaces, Sockets API, $QIO, IO$_TTY_PORT|IO$M_TN_SHUTDOWN, Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 p1
    OpenVMS usage:channel
    type:         word (unsigned)
    access:       read only
    mechanism:    by value
    The p1 argument contains the channel number of the socket to
    establish the TELNET session.