Library /sys$common/syshlp/ncphelp.hlb SET, MODULE, X25-SERVER, KNOWN DESTINATIONS, CALL VALUE hex-value  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 Specifies the string used to test the incoming call data.
 Hex-value is a string of 2 to 32 hexadecimal digits.  By default,
 no value is used.