In messaging, the separator characters are known as the message delimiters or special encoding characters.
||||Field separator, aka pipe|
|^||Component separator, aka hat|
|~||Field repeat separator|
The first two fields in the MSH segment define the separator characters to be used throughout the HL7 message. The MSH-1 field defines the field separator, and the MSH-2 field defines the other separator characters for the message in the following order: component, field repeat, escape character, and subcomponent. Here’s an example of an MSH segment with the defined separator characters in MSH-1 and MSH-2: