We have a trading partner who is sending us a file containing nothing but the TA1 segment as an acknowledgement of a prior transmission for which we requested an acknowledgement by setting ISA14 to ‘1’. Is that a kosher implementation of the TA1? Or should their TA1 segment be enclosed in an interchange (ISA/IEA envelope segments)?
From the examples I’ve seen, I’m thinking that in order for us to receive a TA1, the TA1 segment has to be enveloped by ISA and IEA segments (at least); otherwise, how else would you know what the element and segment delimiter characters should be.
Section B.1.1.5.1 of X231A1 Consolidated on page 66 states that the TA1 "...is a single segment that is transmitted without the GS/GE envelope structure...", and that it "...can be included in an interchange with other functional groups and transactions." However the section does not make it clear if the TA1 may or may not be transmitted outside of an interchange.
Please advise.
Per your question:
Is that a kosher implementation of the TA1? Or should their TA1 segment be enclosed in an interchange (ISA/IEA envelope segments)?
No, this is not correct or treif.
Refer to X12.5 Interchange Control Structures, section:
4.4.1 Basic Interchange Segments
The basic interchange segments consist of the ISA, the IEA, and the TA1 segments.
The trading partner must meet the minimum requirement as stated in X12.5 section 4.4.1