Library /sys$common/syshlp/ncphelp.hlb SET, LINE, NETWORK net-name  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Applies only to X.25 lines. Specifies the network to which the line is
 connected. If only one network is set up, that network is the default.
 Otherwise the NETWORK parameter is mandatory.