DDE Link Statements
The three parts of the link statement (example, @Excel|c:\Excel\file.xls!r2c2:r4c4) are described as follows.
@Source application| First, specify the source (or server) application (in the above example, the source application is Excel). The source application must be separated from the rest of the link statement by a "|". You also need to designate whether the DDE link is "hot" (place an "@" in front of the source application to indicate that the client file is updated whenever the server file is changed) or "cold" (place a "^" in front of the source application to indicate that the client file is updated only when the user requests it or changes it back to "hot").
Topic! The topic designates the name (and path) of the file in the source application and must be separated from the rest of the link statement by a "!" (be sure to establish the full path name for the file). In the above example, the topic (c:\Excel\file.xls!) designates not only the name of the Excel file (file.xls) but also the drive and directory that the file is in (example, c:\Excel). How you identify the source file depends on the source application that you are using (refer to your source application for information on how to designate the Topic.
Item Next, specify the cell, range, named range, or some other name specific to your source application. What you specify here is dependent upon the source application (refer to your source application for information on how to designate the item. In the above example, a range in the Excel spreadsheet is defined (example, r2c2:r4c4 specifies the block "from row number 2, column number 2 to row number 4, column number 4").
See also: DDE Links - Overview, DDE Link Types.