There are some systems in the market for which an ordinary ACK message is not enough. For instance, one system Partners Healthcare had to deal with required that the ORU and ORM messages have an ACK sent back that had 'ORR' as the message identity instead of 'ACK'.

Fortunately it is very easy to customize the behavior of auto-acknowledgments. In this case the solution was to store the MSH 9 field in a Python variable called MessageType. The outbound script for the MSH 9 field was then changed to use the following simple piece of code:

if (MessageType == 'ORU') or (MessageType == 'ORM'):
   value = 'ORR'
else:
   value = 'ACK'

Flexibility is definitely important when facing varied problems.