If you choose to restrict processing to only those records within a given ZIP Code range, type a low ZIP Code and a high ZIP Code. Note that CODE-1 Plus assumes that your input file is sorted by ZIP Code. For this reason, if CODE-1 Plus encounters a record with a ZIP Code that is alphanumerically lower than the low ZIP Code you typed, that record will not be processed, and CODE-1 Plus will proceed to the next record. If, however, CODE-1 Plus encounters a record with a ZIP Code alphanumerically higher than your specified high ZIP Code, it will assume that all of the remaining records also have higher ZIP Codes, and CODE-1 Plus will treat the record as the end of the file.