Library /sys$common/syshlp/ncphelp.hlb SET, EXECUTOR, INACTIVITY TIMER seconds  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Specifies  the  maximum duration ofinactivity (no data in either
 direction) on a logical link before the node checks to see if the
 logical link still works. The range is between 1 and 65,535.  If you
 do not specify this parameter, the default value is 60.