title: What is the HL7 ZDS segment used for?
body: <p>My very old HL7 parser has just hit a snag as it is now getting some messages with a ZDS segment present.  It was easy to fix by adding a ZDS object to my parser, but I am trying to find out what it is used for.  Googling hasn't helped much.  This is a sample</p>
  
  <pre><code>ZDS|PERFORM|p0001236^PATEL^ATEST^^^^^^HHB_INOP_PRSNL^^^^OTHER|20100714101800|CD:653
  ZDS|TRANSCRIBE|p0001236^PATEL^ATEST^^^^^^HHB_INOP_PRSNL^^^^OTHER|20100714101800|CD:653
  ZDS|SIGN|p0001236^PATEL^ATEST^^^^^^HHB_INOP_PRSNL^^^^OTHER|20100714101912|CD:653
  </code></pre>
  
  <p>So, I'm interested in what each field is though looking at this sample data, it seems I don't lose much by just dropping the whole segment.</p>