DS0A

DS0A is the interface most commonly used for SS7 networks in the US. It is a 56/64kbit/s channel typically located in a DS1 or larger facility. The DS0A electrical interface usually only exists inside a central office environment, and only exists for the sole purpose of connecting into a channel bank to be multiplexed onto a higher facility.

Sources

• Cisco SS7 Fundamentals
• Russell, Travis. "Signaling System # 7", Mcgraw-Hill Telecommunications. ISBN 9780071822145