Sennheiser Cisco adaptor cable for electronic hook switch - 8900 and 9900 series, terminated in USB Cisco 8900 series and Cisco 9900 series adapter cable for electronic hook switch, suitable Suitable for DW Office, DW Office ML, DW Office Phone, DW Pro 1, DW Pro 1 ML, DW Pro 1 Phone, DW Pro 2, DW Pro 2 ML, DW Pro 2 Phone, SD Office, SD Office ML, SD Pro 1, SD Pro 1 FEATURES_ * Remotely answer your phone calls * Handle all calls by the press of a single button, i.e. end the call * Get notified from the distance about incoming calls by the ring tone in the headset