==== 9.4.1 T=0 Specifics for Outgoing Data Transfers ====

The **setOutgoing** and **setOutgoingNoChaining** methods in the **APDU** class are used to specify that data needs to be returned to the CAD. These methods return the expected length (**Le**) value as follows when extended length semantics are not enabled (see [[9.4.4.1_Extended Length API Semantics| Section 9.4.4.1, Extended Length API Semantics]]): 

**ISO 7816-4 CASE 1**: Not applicable. Assume Case 2 

**ISO 7816-4 CASE 2**: P3 (If **P3=0, 256**) 

**ISO 7816-4 CASE 3**: Not applicable. Assume Case 4 

**ISO 7816-4 CASE 4**: **256** 

For compatibility with legacy CAD/terminals that do not support block chained mechanisms, the **APDU** class allows a non-chained transfer mode selection via the **setOutgoingNoChaining** method. The related behaviors are discussed in the following sections.