The U-21S is a line input module to be used in conjuction with the 900 series components and other TOA's equipment. It has an unbalanced input with screw terminals, remote volume control function, and gain control.

• For unbalanced, line level sources such astuners, cassette decks, CD players, computer sound cards, jukeboxes, mixers and satellite receivers
• Use for adjacent sources (less than 15ft from the host unit)
• Allows remote control of input signal using an external 10kO linear-taper potentiometer
• Master Remote Volume mode
• Connector: screw terminal