>Hi all,
>
>Has anyone experience in implementing communications with the HL7 (Health Level 7) protocol within VFP ?
>
>If so, how is this done ?
>
>Walter,
Hi Walter,
There are 2 layers of communication you need to consider:
1) Network/Transport layer: A lot of systems are using TCP/IP protocol to provide comunication of HL7 messages. However, some systems on IBM mainframe are pretty much relying on SNA/LU6.2 protocol to provide channel/session to exchange messages.

2) Application Layer: HL7 standard provides ACK message type to handle ACK/NAK. The standard (commonly used are ver 2.2 and 2.3, for more info.,
check out HTTP://WWW.HL7.ORG.) describes many different kinds of HL7 message
Type/Event, e.g message type ADT for Admission, Discharge and Transfer; message type ORM/ORU to handle Lab. Order and Result. There are usually 2
mode of exchanging messages i.e. soliciting and unsoliciting. Unsoliciting
method only sends messages when they are triggered by certain events/activities of the sending system. On the other hand, HL7 standard
provides HL7 Query and Response to handle soliciting method, in which the
client system sends an HL7 Query message and the server system process the query and send back the Response message). There are also different type of HL7 Query and Response messages.
To have a succeeful HL7 interface, it pretty much relies on both parties knowing what kind of messages are supported and what and how segments/Fields are implemented. From our experience, HL7 is an standard but the implementation of the standard differs from one system vendor to another.

We here at State University of NY, Downstate Medical Center are using and implementing HL7 standard for about 3 years and exchanging different kind of
messages between ADT, Lab, Pharmacy, Radiology and other systems using an
interface engine (CERNER Open Engine) as the communication hub handling both LU6.2 ansd TCP/IP comm. protocols. We also wrote a few custom VB and VFP programs to handle HL7. VB program uses Winsock activex control to habdle network protocol and VFP handles parsing and updating of the HL7 messages.

Kam.