Library /sys$common/syshlp/ncphelp.hlb SET, MODULE, X25-PROTOCOL, DTE dte-addr, INTERRUPT TIMER seconds  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 This is the interrupt timer (ISO T26 timer).  This parameter can
 only be used with the ISO8208 profile.  Specify a value in the
 range 1 to 255.  If you do not specify a value, there is no time
 limit on interrupt acknowledgments.