KAY Elemetrics Computer Speech Lab 4400 Unit. Connects to host PC via USB interface and provides Audio and Digital I/O for Speech and Sound Analysis work. Front panel controls: Input Level for Channel 1 and 2, Volume and Balance for Headphone Output. Audio output via 1/4in. Stereo Headphone Jack. Channel 1 input via RCA, XLR, and 1/4in. Microphone Jacks. Channel 2, 3, 4 inputs via RCA Jack. Rear Panel Connections: Digital Interface I/O via RCA Jacks, Channel 1 and 2 Outputs, both Speaker and Line-Level, via RCA Jacks. USB-B Interface to HOST PC, 100-240 VAC 50/60 Hz Power Input, via IEC 'D' Jack. SN: 14602-32, Service ID: 30628