IHE给出了各个Actor之间如何通讯的建议： 1.      应用程序通讯时必须用MLLP包装或者解析。 2.      客户端建立连接后，服务器端必须用此连接进行应答。客户端可以继续用此连接启动新事务 原文如下： 1.     Applications shall use the Minimal Lower Layer Protocol defined in Appendix C of the HL7 Implementation Guide. 2.     An initiating application that wants to send a message (initiate a transaction) will initiate a network connection to start the transaction. The receiver application will respond with an acknowledgement or response to query over the open connection. The initiating application can initiate a new transaction on the same connection. However, the initiating application must be able to handle cases where the connection has been closed due to possible timeout by the accepting application. For example if the initiating application does not submit a request over the connection in a timely manner, the accepting application has the right to close the connection. When this condition is detected, the initiating application needs to open a new connection for subsequent requests. 在实现消息解析时，请参考IHE_ITI_TF_Rev8-0_Vol2a_FT_2011-08-19的3.8，3.9，3.10以及IHE_ITI_TF_Rev8-0_Vol2x_FT_2011-08-19的Appendix C 有必选Segment，以及每个Segment必选element,其中 RRequired R2This is an IHE extension. If the sending application has data for the field, it is required to populate the field. If the value is not known, the field may not be sent. R+This is an IHE extension. This is a field that IHE requires that was listed as optional within the HL7 standard. OOptional CConditional 总共是8个必选Segment，但是对于具体事务有些Segment可以不关心，比如Feed不太关心PV1. [...]表示“可选” {…}表示“可重复” [{…}]表示“可选，且可重复” PIX总共包括3个事务：Feed，Query，Update，HL7版本分别为v2.3.1， V2.5， v2.5. Feed包括：A01，A04，A05，A08。MessageType为ADT，A01-A08， ADT_A01. 以及A40，MessageType为ADT，A40， ADT_A39 Query包括：Q23，K23 Update: A31 在PIX中需要对域进行配置， 有几个概念需要澄清。 病人标识源： 就是ADT消息的SendingApplication字段。 病人标识域： 病人交叉索引域：