If you're looking at this you probably know what it is - it is to connect Bang & Olufsen telephone equipment to the phone line and the power adapter.  Compatible with Beocom 6000 phone, Beolione Mk1 PSTN, or Beotalk 1100 and 1200 answer machines.

This is the 'dot' type which means it requires a crossover telephone cable - the one normally provided by B&O.

Please ensure your equipment is compatible before buying - no returns.