An FATS index file may contain more than one record with the same key. With this command your application can determine the record corresponding to the first key value which is greater than and different than the key recently returned by one of the browser commands ("A", "E", "F"...), which have to be executed as the latest command.
Unlike the command Search Next (N), this command skips over duplicate keys.Each modification of the index file by inserting or deletion of keys makes an internal pointer invalid that is necessary for this instruction. You better use the command Search Next Different After (AD) because this can happen in the network environment from any station.
If there is no key in sequence FATS will return an errorcode of 15.