Ill. Admin. Code tit. 83, § 1328.300 – Wireless Service Provisioning

a) Wireless 9-1-1 service connects a person who has dialed 9-1-1 to the appropriate 9-1-1 system provider. Wireless 9-1-1 service shall be provided by wireless carriers in a manner that allows the 9-1-1 system provider to comply with 83 Ill. Adm. Code 725.
b) Diverse routing shall be provided for all wireline trunking facilities used to transport and terminate the wireless 9-1-1 call where facilities are available.
c) Default routing shall be provided in the event that a wireless 9-1-1 call cannot be selectively routed. The level of default routing shall be negotiated among the 9‑1‑1 system provider, the wireless carrier, and the 9-1-1 authority.
d) Wireless carriers shall provide information to the appropriate 9-1-1 authority of changes that affect the identification and location information needed by an authorized wireless 9-1-1 answering point at least 10 business days prior to changes being made. The media used in providing this information shall be mutually agreed upon by the carrier and the 9-1-1 authority.
e) Prior to an authorized wireless 9-1-1 answering point going on-line, wireless carriers shall identify a primary point of contact and telephone number for each 9‑1‑1 authority. Wireless carriers shall adopt practices to notify this primary point of contact within 15 minutes:
1. 1) after a confirmed outage with the system, as well as the magnitude of the outage; and
2. 2) after the confirmed restoration of 9-1-1 services.
f) When all 9-1-1 circuits are busy in the originating mobile switching office, the switching facility, if equipped to provide the function, shall route the caller to an announcement, busy tone or reorder tone. When an all-trunks busy condition occurs in an intermediate switching facility, that machine shall, if equipped, route the caller to an appropriate backup answering location, announcement, busy tone or reorder tone.
g) Wireless carriers shall provide each 9-1-1 authority with an emergency phone number or numbers that are available 24 hours per day, 7 days per week for network and security support.