A T1 line is a high-speed digital data transmission service that uses 2 twisted pair copper wires to transmit and receive data or voice traffic. It is commonly used in businesses to deliver voice and data lines, and it is a specific type of "trunk" or transmission channel between two points. A T1 line can transmit data at a speed of 1.544 Mbps, making it an important step forward in delivering higher speed connections compared to standard telephone lines. T1 lines are also known as T1 Internet, and they are used for high-speed data transmission, internet access, and voice, depending on the type of T1 and the configuration. T1 lines have been a stable business offering of phone companies for decades, and they are known for their consistency, predictability, and reliability. However, T1 lines are becoming more expensive, and there are now many T1 alternatives that provide more affordably-priced bandwidth in conjunction with better performance and more flexibility. T1 lines are typically used as a "last mile" connection for businesses to access the publicly switched telephone network (PSTN) .