3.5mm to 2.5mm Adapter The 3.5mm to 2.5mm Adapter is ideal for all users of Sennheiser Speakerphone Series SP 20 and SP 20 ML, in combination with many wireless DECT handsets* The adapter cable is used to connect DECT wireless handsets, equipped with a 2.5mm headset interface to the Sennheiser Speakerphone Series SP 20 and SP 20 ML. Please note that this adapter is not approved for use with wired desk phones due to potential grounding loops between the 3.
