A feature activated when an incoming 9‐1‐1 call cannot be selectively routed due to an ANI failure, garbled digits, or
other causes. Such incoming calls are routed from the IEN Control Office to a default PSAP designated by the customer.
If there is an incident where several people are dialing 9‐1‐1 and the PSAP runs out of ESRKs, the FMCC will send the
ALI/ACK, because all the other numbers are in use. An ALI/ACK can also occur if the cell carrier field in the gsmcell/cell
table has a carrier ID for which there is no esrkpool table built. It will also occur if there is a mismatch between the ESN
loaded on the cell/gsmcell table and the one loaded on the esrkpool. This number is provisioned in the PSAP table.