Provides a Technical Acknowledgment (TA1) to the Interchange sender that reports the status of the processing of an interchange header and trailer by the address receiver:
If the ISA and IEA of a received X12 message are valid, the host sends a positive TA1 ACK, regardless of the status of the other content.
If the ISA and IEA of a received X12 message are not valid, the host sends a TA1 ACK with an error code.
The TA1 ACK is sent inside an ISA or IEA envelope. The ISA and IEA are no different than any other interchange.