SS7 (Signaling System 7)

SS7 (Signaling System 7) is an out-of-band signaling system used to provide basic routing information, call set-up and other call termination functions. Signaling is removed from the voice channel itself and put on a separate data network.

a.k.a.

CCS7 (Common Channel Signaling 7)

NENA-STA-010, NENA i3 Standard for Next Generation 9-1-1