The UK communications industry regulator, Ofcom, has told internet telephony providers that they must now allow emergency 999 calls over their networks or face the risk of enforcement action.
Caller location information must also be provided where technically feasible.
Effective immediately, the ruling for Voice over Internet Protocol (VoIP) providers affects businesses such as BT, Vonage and Skype that offer services that connect VoIP calls to the public telephone network.
Operators must now provide the ability to make calls to 999, the emergency number used in the UK, and 112, the number most used in other EU countries.
Ofcom had previously told operators to place stickers on equipment or on-screen labels indicating whether or not emergency calls were possible over a service.
The rule, known as General Condition 4 of the General Conditions of Entitlement, also provides that the network operator must provide Caller Location Information for calls to the emergency call numbers "to the extent that is technically feasible".
Ofcom said that ‘technically feasible’ should be taken to mean that location information must be provided where the VoIP service is being used at a predominantly fixed location.
In May, a child died in Calgary, Canada after an ambulance was dispatched to the wrong address in response to an emergency call placed by his parents using a VoIP phone. The ambulance had been dispatched to an address in Ontario, 2,500 miles away.
The requirements already apply to fixed line and mobile communications providers but the VoIP industry had resisted their extension.
In December last year, the Voice on the Net (VON) Coalition Europe was set up as a lobby group to influence the regulation of internet telephony.
The group, which includes Google, Microsoft and Skype among its founding members, warned against the “premature application” of emergency call rules to VoIP services that are not a replacement for traditional home or business phone services".
The VON Coalition said the move "could actually harm public safety, stifle innovations critical to people with disabilities, stall competition, and limit access to innovative and evolving communication options where there is no expectation of placing a 112 call".