The HL7 Listener uses an Auto ACKnowledgement to generate ACK messages. The settings used to configure the format of the ACK messages are stored in the listener.vmd, which ships in Chameleon's application directory (e.g. C:\Program Files\iNTERFACEWARE).

	Sometimes you might need to change the listener.vmd file when dealing with systems which are not HL7 compliant. For instance, you might need to alter the pre-processing python script to remove illegal embedded 0x0D characters. See the python scripting documentation for more details.