Adapter cable with 2 different connectors on both ends

Unfortunately, from the description not clear that it is the adapter with 3 cables.
In each case, different plugs on both ends of the cable.
If you want to connect as an ISDN telephone to an ISDN module, you can not.
Who the need, for that is certainly helpful.
One should therefore vergiewissern before ordering here exactly whether it is what you need.
If it fits, the price is right!