DESC: The M3905 Call Center phone is designed to satisfy the specialized needs and enhance the productivity of the most demanding call center agents and supervisors. The M3905 includes a direct-connect headset for agents, as well as a supervisor port. This headset port works in conjunction with the Supervisor Observe button that allows them to listen in on an active call, or listen and talk. The M3905 increases your customer service capabilities and productivity through efficient, professional call processing.