In the handset menu go to:
Settings - Registration - Basic Registration
When Basic registration is started, the handset will start a pure GAP DECT registration. (Make and Receive calls only) This can be used when registering against very old incompatible Base-stations.
We will list on this FAQ page the Base-stations where this should be used. For now, the list is empty.
Normal DECT Registration is started using the menu: Settings - Registration - Register handset