Government Emergency Services and VoIP
PSTN and Emergency Services
Many countries throughout the world use a three digit telephone number to provide citizens with access to emergency services. The number to be dialled varies between nations such as 911 in the United States or 112 in the European Union but their purpose is similar - to connect callers with operators who can direct emergency services such as fire trucks or police officers to the emergency location.
With traditional PSTN systems, each handset is associated with a location that is maintained by the telephone provider. When a call is received by an emergency responder, the location of the caller is automatically retrieved from national databases and displayed on the console. This enables the operator to send help even if the call is terminated or the caller is unable to provide their location. Such a situation can easily arise if an elderly citizen or a small child is making the emergency call.
How VoIP Deals with the Problem
However one of the advantages of VoIP is that users can place calls from anywhere. Portability means that the VoIP service provider may not be able to provide precise location information for every one of their subscribers. At most, the vendor might have the location associated with a particular IP address and even this data may not always be accurate. For example an employee may be making a phone call from his home through the VPN of his employer, in which case the location would indicate the business rather than the residence address. There is a real danger of emergency personnel being sent to the wrong location in this manner.
In order to prevent such situations, the FCC has mandated that interconnected VoIP services have to provide E911 calling features for their users. Further, the feature has to be enabled by default and customers are not allowed to opt out. In most cases, the provider also has to give an easy way for subscribers to register and change their location, so that the information is always up to date. E911 may not be accessible if the power goes down and if so, providers should communicate such limitations within the business VoIP setup.
Of course, the above requirements are only applicable to interconnected VoIP services and providers who offer only VoIP calls (which do not touch the PSTN at any point) are exempted. However they are also required to inform their subscribers that emergency calling will not be available on their service. E911 still has some differences with the regular emergency calling services but VoIP providers are working hard to bring feature parity between the two.