Hear ring tones, answer and end calls, adjust the volume or mute a call up to 450 ft. from your desk with this hook switch adapter. Simple plug-and-play solution that converts from the HHC standard used in Cisco phones to the DHSG standard used in Jabra headsets and vice versa. Improve work efficiency and ergonomics throughout the day with wireless freedom. For Use With: Jabra GO™ Series; Jabra PRO™ Series; Cisco Unified IP Phones 7900G Series.