The checksum enables the initiator of any transaction to perform a sanity check of any specified bank account number on their own computer prior to actually initiating a request. For example, sorting code 00-00-00 would represent the main bank office, and the first subbank office registered would have the suffix 01.
IBAN and BIC codes are widely used means of identifying bank account numbers, but not the only international system.
Also the name of such a code varies. UK clearings systems:
UK Clearing systems
BACS: Bulk electronic clearing
CHAPS Sterling: High value, same day sterling payment clearing
CHAPS Euro: High value, same day euro payment clearing
Cheque and Credit Clearing: Cheque clearing for Great Britain & Northern Ireland.
Fields format is: SORT CODE, BANK NAME, BIC, ADDRESS INFORMATION
'160063','THE ROYAL BANK OF SCOTLAND PLC','RBOSGB2122','LONDONMARYLEBONE Chatham Customer Service Centre Western Avenue Waterside Chatham Marine ME4 4RT Phone: (845) 6014082 Chatham England'
'160079','THE ROYAL BANK OF SCOTLAND PLC','RBOSGB2121','LONDON MAYFAIR Southampton Customer Service Cent Brunswick Gate 23 Brunswick Place SO15 2AQ Phone: (2380) 836339 Southampton England'
'160080','THE ROYAL BANK OF SCOTLAND PLC','RBOSGB21604','PRIVATE BANK CHILDS Chatham Customer Service Centre Western Avenue Waterside Chatham Maritime Kent ME4 4RT Phone: (845) 6014082 Chatham England'
A Bank Code is a code assigned by a central bank, a Bank Supervisory Body or a Bankers Association in a country to all its licensed member banks.