dio interface are transported by a dedi- cated FVC (network to MS) and RVC (MS to network). The number of FVCs and RVCs in a cell depend on expected traffic intensity in the cell. 3. Message exchange within the process control system is occasionally needed in data phase, e.g. for handover and for output power control of the MS. In that case, the FVC and RVC are borrowed for about 100 ms, which normally is not noticeable for the voice user. 4. The selection of FVC and RVCs, power control and some other properties of the RF transport node are controlled by the terminal process controller over a trans- port control CSI. 5. The basic structure of the terminal process controller logical node is defined by how the channels are used. The SAH handles SDUs that are transported on FOCC and RECC, while the protocol element In-service control is directly con- nected to the transport node, and handles SDUs that are transported over FVC and RVC in data phase. 6. The FOCC is handled by an Integrator, which performs discrimination and some TAH functions. The Integrator can distinguish between two types of received SDUs: those that represent messages terminated by the Broadcast data handling element, and those that represent messages terminated by the Service access control element. 7. The Integrator protocol consists of a repeating sequence of message types, called MessTrain. The broadcast handling protocol consists of a sequence of different message types. This sequence is called OvhMessTrain. The service access con- trol protocol also consists of a sequence of different message types. This sequence is called McsMessTrain. Finally, in data phase, different InServCall- Control messages are exchanged in the in-service control protocol. Note that the integrator and broadcast data-handling protocols consist only of received messages, while the other protocols define dialogues (i.e. messages in both directions). In the following we will take a closer look at how the integrator and the broad- cast protocol messages are encoded, forma