Signaling System No. 1, also known as SS1, is a telecommunications signaling protocol used primarily in the North American telephone network. It facilitates the setup and teardown of telephone calls by transmitting control information between switching systems. SS1 is essential for managing call routing and ensuring efficient communication. This system operates over the Public Switched Telephone Network (PSTN) and is designed to handle various signaling tasks, such as call establishment, supervision, and disconnection. SS1 is a fundamental component of traditional landline telephony, enabling reliable connections between callers and recipients.