ESRD (Emergency Services Routing Digit)
ESRD (Emergency Services Routing Digit) is a 10-digit North American Numbering Plan number that uniquely identifies a base station, cell site, or sector that is used to route wireless emergency calls through the network. The ESRD may also be used by the PSAP to retrieve the associated ALI data.
Relevant NENA Documents
NENA 03-507, ESQK Guidelines for VoIP to E9-1-1 Connectivity