VMS Help DECnet-Plus, DCL Commands, SET, HOST, /X29, Qualifiers, /SUBADDRESS=string  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /NOSUBADDRESS

    (Default=/NOSUBADDRESS)

    If you use this qualifier, the digit  string  you  specify  is  a
    local subaddress in the outgoing call.