The parameter packet is a location in application storage where the caller indicates the action to be taken if no event queue data is available. The format of the parameter packet is as follows:

┌─────────────────────────────────────┐
│Field         Length     C Datatype  │
├─────────────────────────────────────┤
│Read type     WORD       USHORT      │
└─────────────────────────────────────┘