Library /sys$common/syshlp/nclhelp.hlb SNA Peer Server Module, SDLC, Link subentity, enable  *Conan The Librarian (sorry for the slow response - running on an old VAX)

   enable sdlc link

   The enable sdlc link command places the SDLC Link subentity in its
   enabled state (on).  An association may be made between the Link
   subentity and the Modem Connect Line entity of the physical line
   on which the protocol operates.  For more information about Modem
   Connect Line refer to the DECnet-Plus Network Control Language
   Reference.

   Ex,   ncl> enable sdlc link sdlc-0