5.16.17.2. Service Information 
- The number of channels that remain reserved for direct connections is stipulated pursuant to ITU-T E.412 and cannot be altered through an explicit parameter, but only implicitly via the number of configured circuits of a trunk group.
- The parameter TDDRFLAG is always set to ON as the default value when setting up a new trunk group.
- This function is service-independent and applies both to analog and digital channels.
- The number of reserved channels can be queried by means of AMO BUEND.
- For the special case of a single configured circuit, the parameter TDDRFLAG=OFF should be set.
- If, during path selection, a route is selected in which the attribute ALTTGR is active, this property is transmitted to the network (e.g. with Cornet Protocol) and also taken into account in subsequent path selections in the network.