Legacy Selective Router Gateway (LSRG)
The LSRG provides an interface between 9-1-1 Selective Routers and NG9-1-1 Emergency Services Networks. It enables calls to be routed and/or transferred between Legacy and NG9-1-1 networks. It is used in some network deployment models for the transition from Legacy 9-1-1 to NG9-1-1.