SR (Selective Router) is the Central Office that provides the tandem switching of 9-1-1 calls. It controls delivery of the voice call with ANI to the PSAP and provides Selective Routing, Speed Calling, Selective Transfer, Fixed Transfer, and certain maintenance functions for each PSAP.
Also known as:
9-1-1 Selective Routing Tandem
E9‑1‑1 (Enhanced 9‑1‑1) Control Office
E9‑1‑1 (Enhanced 9‑1‑1) tandem Office
Relevant NENA Documents