The JPL EHS-5 DHSG-PLC Polycom Adapt Cord electronically connects your DECT headset base to your telephone. It enables remote operation, answer/end calls, eliminating the need for a mechanical handset lifter. For wireless headset use with various phones. Compatible with Polycom IP 320, 321, 330, 331, 335, 435, 450, 550, 560, 650, 670 & VVX: 300, 310, 400, 410, 500, 600 and 1500 phone models.