Does it matter what number is sent to E911?
Yes. The number sent to the E911 operator as the calling number is not only for association with the correct address, it also serves as the callback number for the operator if the call disconnects. For that reason, it is best to use the caller’s own number if possible, since that allows any callback to route directly to the person who needs assistance. You can configure this behavior by selecting Use as the ANI only if the phone or user doesn’t have a phone number Location option.
If your agents do not have individual numbers, or if those numbers are not reachable externally, then use an ELIN. Because the number serves as a callback contact for Emergency Services operators, Genesys recommends that the ELIN be a number associated with a phone in the same physical location, such as a front desk or security desk. Do NOT use an IVR number as an ELIN, since an operator performing a callback cannot reach the actual person needing assistance.