3.10.2.3. Restrictions 
- DMC is not supported for remote office phones.
When the terminal is registering at the OpenScape 4000 SoftGate, it is detected as a remote subscriber and therefore automatically not treated like a DMC endpoint by the system, regardless of the AMO SDAT parameter DMCALLWD. To support partial DMC routes to the last possible endpoint (in this case the OpenScape 4000 SoftGate itself) it is recommended to activate DMCALLWD in AMO STMIB for the OpenScape 4000 SoftGate.
- The typical plug’n’play function is supported for remote subscribers but not in connection with DLS synchronization. If a synchronization has been started between OpenScape 4000 Assistant/Manager and DLS, the gateway IP addresses of the remote subscribers will be overwritten in the DLS database. They must be manually changed to the WAN gateway IP address afterwards.
- SIP/UFIP SRS does not support "mobile HFA" feature and it is necessary to have unique phone number for local phone and different one for SRS.
- The feature Secure Remote Subscriber is available on STMIX/STMIY only for SIP.
- HFA is only possible on SoftGates.
- Parallel connections of SIP SRS from LAN and WAN to the same gateway are not possible. The SRS for SIP phone numbers can only be connected via WAN interface.