• Antenna Cable TV: This indicates that the amplifier is suitable for both antenna TV signals and cable TV signals, making it versatile for various signal sources.
• 3 Equal Carriers: This suggests that the amplifier is capable of processing and amplifying three equal carriers, which may refer to specific channels or frequency bands within the signal.
• Professional Digital Signal System: It implies that the amplifier is designed for use in professional-grade signal distribution systems and is capable of handling digital TV signals, including high-definition television.
• High-Quality CATV Indoor Amplifier A20: This identifies the amplifier as an indoor model, and “A20″ may be a specific model or product identifier used by the manufacturer.

Indoor amplifiers like the one described are used to enhance the strength and quality of TV signals within indoor environments, such as homes or commercial buildings. They are crucial for maintaining signal quality and reliability when distributing cable TV and antenna TV signals to multiple televisions or devices.