Q. I saw on the news that a bunch of cellphone users couldn’t connect to the 911 emergency number the other week because of an “outage.” Why is dialing 911 different on a mobile phone than on a landline?
A. When someone dials the national 911 number, a nearby call center for emergency services (known as a public safety answering point, or P.S.A.P.) picks up the call and the operator dispatches medical technicians, police, firefighters or personnel from another appropriate agency in the area. This month, calls from AT&T wireless users in at least 14 states would not go through to the emergency network from AT&T’s own cellular airwaves for several hours, possibly because of a malfunction with the software routing the calls to the 911 centers.
Ajit Pai, the chairman of the Federal Communications Commission, issued a statement the day after the disruption to say the agency was looking into the cause. However, AT&T is not the first or only wireless carrier to have problems connecting customers to 911 services. Among the previous cases, an F.C.C. investigation into a Verizon outage and a failure to provide emergency-call service to some subscribers in 2014 resulted in a $3.4 million settlement.
A page devoted to 911 wireless services on the F.C.C.’s website explains the challenge of handling emergency calls from wireless phones instead of wired landlines. The agency notes that because “wireless phones are mobile, they are not associated with one fixed location or address” like landlines. While the mobile phone can provide the location of the nearest cell tower, those coordinates may not be specific enough for a 911 dispatcher to use for directing a responder.
When calling 911 from a wireless phone, be sure to give your exact location and phone number immediately in case you are disconnected.
To help pinpoint calls, some carriers use Enhanced 911 services to provide dispatchers with more precise information, like the geographical coordinates of the mobile phone, but not all P.S.A.P. centers have the technology to receive the data. The major national carriers AT&T, Sprint, T-Mobile and Verizon all have information on emergency-calling services on their sites.