Determines whether to perform a check when an incoming call matches this call details entry based on the
contents of the user-user information in the incoming SETUP message. The value 'off' means that the check
is not carried out. The value 'local' means that the check is carried out and the user-user information
is compared with the call details entry name. The value 'remote' means that the check is carried out and the
user-user information is compared with the call details entry remote name. A number of checks are
optionally carried out once a matching call is found. The first check is against the called subaddress in the
SETUP message, then against the user-user information in the SETUP message, then against the calling number
information in the SETUP message.