Document types and codes
Document type codes
| Code | Document | Notes |
|---|---|---|
380 | Commercial invoice | The standard case |
381 | Credit note | Requires a preceding invoice reference — see IBR-032-OM |
383 | Debit note | Same preceding-invoice requirement |
386 | Prepayment invoice | |
389 | Self-billed invoice | Buyer issues on the supplier's behalf. Restricted by IBR-177-OM |
261 | Self-billed credit note | Requires a preceding reference and is restricted by IBR-177-OM |
BTOM-001 — invoice transaction type
Every Oman document carries a 20-character bitmap of 1s and 0s with at
least one bit set. It travels in the name attribute of the type code element,
not as a separate field:
<cbc:InvoiceTypeCode name="00100000000000000000">389</cbc:InvoiceTypeCode>
Fifteen of the twenty positions are defined; the rest are reserved. Two examples that appear in the rules verbatim:
| Bitmap | Meaning |
|---|---|
00100000000000000000 | Self-billed invoice / credit note |
00000000100000000000 | Invoice for import of services under reverse charge |
IBR-001-OM enforces the shape — exactly 20 characters, [01] only. Several
other rules then key off individual positions, so a structurally valid bitmap
with the wrong bit set still fails.
IBR-177-OM — self-billing is not general purpose
A self-billed invoice 389 or self-billed credit note 261 is only valid when
BTOM-001 is one of a short list: self-billed, import of services under reverse
charge, profit-margin self-billing, or import of goods. Self-billing outside
those cases is rejected — this is a policy rule, not a formatting one.