TSPI Phone Device Structures

Note  Some structures include Size and Offset fields for defining the location and length of strings in the variable portion of the structure. If the service provider is requested to add a string but no string is available, the service provider must indicate this condition in one of the following ways:

• Set both the Size and Offset fields to 0.
• Set the Offset field to nonzero, but set Size to 0.
• Set the Offset field to nonzero, set Size 1, and the set the byte at the Offset to 0.