ISO 6523

ISO 6523 defines a "Structure for the Identification of Organisations (SIO)". This is a syntax for uniquely identifying organizations in computer data interchange.

It is composed of:
* 4 digit ICD (International Code Designator), which uniquely identifies the authority which issued the code to the organisation.
* organisation code, up to a maximum of 14 characters (A-Z, 0-9, space or hyphen).
* organisation name, up to a maximum of 250 characters

The ISO 6523 standard suggests, but does not require, that the solidus be used to separate the above three fields in data transmission, and that two consecutive soliduses be used to terminate the SIO. However, applications and other standards that reference ISO 6523 are free to adopt alternative syntax and still remain conforming.

It also permits the omission of the organisation name, if both parties to the transmission agree. Furthermore, if only one authority is used by an application, the ICD may be omitted.

Registration authority for ICDs is the British Standards Institution. An (outdated) list of allocated ICDs is available [http://asn1.elibel.tm.fr/oid/doc/ICD-list.htm here] . An up to date list may be acquired by contacting the BSI.

ISO 6523 forms the basis of OSI naming under ISO 8348. It also forms the 1.3 OID tree.