This section discusses the SWIFT field structure. A field is a logical subdivision of a message block A, which consists of a sequence of components with a starting field tag and delimiters.
A field is always prefaced by a field tag that consists of two digits followed, optionally, by an alphabetic character. The alphabetic character is referred to as an option. For example, 16R is a tag (16) with an option (R) that indicates the start of a block; 16S is a tag (16) with an option (S) that indicates the end of a block. A field is always terminated by a field delimiter. The delimiter depends on the type of field used in a message block.
There are two types of fields used in SWIFT messages: generic and non-generic. The type of field used in a SWIFT message block is determined by the Message Type. What follows is a discussion of these SWIFT field structures. For more on generic and non-generic fields and how to distinguish between them, see Part III, Chapter 3 of the SWIFT User Handbook
The structure of non-generic fields in SWIFT message blocks is as follows:
:2!n[1a]: data content<CRLF>
where:
: = mandatory colon
2!n = numeric character, fixed length
[1a] = one optional alphabetic character, letter option
: = mandatory colon
data content = the data content, which is defined separately for every tag
<CRLF> = field delimiter
The following is an example of a non-generic field:
:20:1234<CRLF> :32A:...<CRLF>
The structure of generic fields in SWIFT messages is as follows:
:2!n1a::4!c'/'[8c]'/'data content
where
:2!n1a: = same format as non-generic fields, except that 1a is mandatory
: = mandatory second colon (required in all generic fields)
4!c = qualifier
'/' = first delimiter
[8c] = issuer code or Data Source Scheme (DSS)
'/' = second delimiter
data content = See Part III, Chapter 3 of the SWIFT User Handbook for the format definition
The following character restrictions apply to generic field data content: