Andrea Electronics C1-1020700-1 Model PCTI-3 3-Way Telephone Headset Interface, Designed for Maximum Telephone and Computer Connectivity; 2. 2k Ohm, 5 VDC Microphone Power Provided Key Features Removes the Uncertainty of Legacy PC Audio Quality and Compatibility Issues USB 2. 0 Full Speed Operation Device Class Specification V1. 0 Compliant (Digital Audio Device) USB Stereo Microphone Input and Stereo Speaker Output Small Form Factor is Convenient for Portability with Audio Peripherals Power On / Data Transmit LED Indicator Win98 SE / Win 2000 / Win XP and Vista Compatible Mac OS9/10 (without Andrea Software) Compatible Specifications Mic Input: Microphone power provided: 2. 2k Ohm, 5 VDC Connector: 3. 5 mm jack; “tip”, mic power and audio input; “ring” no connect Headset Output: Headphone output impedance: 8 to 32 Ohms for mono headsets, 16 to 32 Ohms for stereo headsets Signal to noise: 40 dB (min) Connector: 3. 5 mm jack; “tip” right speaker; “ring” left speaker, “sleeve” speaker low Computer In / Out: Microphone Input: 3. 5 mm plug connects to computer mic input Speaker output / headset output: 3. 5 mm plug connects to computer speaker output or headset output Cable Length: 7 feet Multimedia Speaker Output: Connector: 3. 5 mm stereo jack Power: Voltage (Wall transformer supplied): 9 VDC Current Drain: 70 mA (max)