How an OGM works
A structured communication (OGM in Dutch, VCS in French — "gestructureerde mededeling", "communication structurée") has 12 digits: 10 of your own and 2 check digits.
The check digits are the first 10 digits mod 97, with 97 when the remainder is 0. It's written +++123/4567/89012+++
(or with asterisks). Banks reject payments whose check digits are wrong, so a customer can't mistype it — and your accounting software can match the payment automatically.
Choosing the 10 digits
Most businesses encode an invoice number (padded with zeros), sometimes combined with a customer number. Keep it unique per invoice: the OGM comes back
in your bank statement (CODA field 101 or CAMT CdtrRefInf with type BBA) and is how reconciliation finds the invoice.
RF references
The ISO 11649 RF creditor reference (RF18 5390 0754 7034) is the international equivalent, accepted in SEPA transfers everywhere.
Belgian banks accept both; many Belgian customers expect the OGM.