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

 Applies only to X.25 lines.  Resets the maximum number of
 retransmissions of a frame to the default value for the specified line
 or all known lines  in the volatile database, or removes the MAXIMUM
 RETRANSMITS value from  the permanent database.