Any data item transferred between DDE servers and clients must have a specification of its format so that it can be properly interpreted by the other side of the connection. In VA Smalltalk each format is described by a Smalltalk String. Here are the predefined formats available:

The data to be transferred, with one exception, must be provided to the respective DDE object as a ByteArray. For example, if a DDE server is serving up bitmap data, then the server application provides the DdeServerManager a format specification of 'Bitmap' and a ByteArray object containing the bitmap data. The only exception is the 'String' format where the data is always provided to the DDE objects as a Smalltalk String.