Ensuring the connectivity of emergency numbers

A major advantage of Voice-over-IP is that the connection can be used worldwide, regardless of the connection address. However, this can lead to problems with emergency calls:

If no location information can be provided for an emergency call (because the caller is unable to speak), the connection address is determined for the phone number. Emergency services will then be dispatched to this address.

However, to ensure that the correct address can be assigned in an emergency, you should only make emergency calls via a line that has been ordered to the line address at which you are currently located.

• If you are working from home, use your mobile phone number for the emergency call.
• If you are working from home, use your private landline or mobile phone number and not the office number for an emergency call.

The individual call number signaling has no influence on the selection of the emergency call center. We contact the emergency call center that belongs to the customer number's connection address and transmit the correct phone number of the SIP account.

Exceptions to this rule apply to combined phone numbers. More on this in the next section.

If several phone numbers are combined in collective accounts or with the branch capability of the Cloud Telefonanlage, it is conceivable that phone numbers with different connection addresses and area codes are used.

Assigning the address via the customer number would then fall short. Therefore, more complex logics are used to ensure that the appropriate emergency call center is contacted.

With easybell, you can combine several phone numbers in a collective account.

In this case, the emergency call center is selected according to the signaled phone number(CLIP no screening).

• If the phone number is part of the collective account, the emergency call center that belongs to the connection address of this phone number is called. This also applies to extensions of the respective phone number.
• However, if the signaled phone number is not part of the collective account, the phone number of the main trunk is transmitted. This means that the emergency call center closest to the main trunk's connection address is called.

With collective accounts, always make sure that you signal a phone number that matches the line address when the emergency call is made.

With the branch feature, phone numbers of a customer account can be used in the Cloud Telefonanlage of another customer account.

In these cases, the emergency call center matching the area code of the transmitted phone number is contacted.

It is therefore crucial that the outgoing phone number always matches the location/area code of the person making the call.

Emergency numbers can be defined in many telephone systems in order to handle them separately. Some or even all of the points in this article are then implemented automatically.

If in doubt, you should ask the manufacturer whether and to what extent your telephone system supports this function.

In order for the call to take place, both parties must agree on a codec. For Voice-over-IP, it has been agreed that emergency call centers must accept the G.711A codec (see Framework for Emergency Calling Using Internet Multimedia).

Therefore, please ensure that G.711A is correctly configured and available in your telephone system.

Most telephone systems on the market first match internal phone numbers or speed dials when routing calls. Only then is the call routed externally to the respective provider.

If, for example, 110 or 112 are assigned as internal speed dials, all emergency calls would end up at the respective extension, but not at the emergency call center. For this reason, the easybell Cloud Telefonanlage does not allow 110 and 112 to be assigned as internal speed dials.

Telephone systems often modify phone numbers before they are transferred to the service provider. A common example of this is that the country code and area code are automatically placed in front of a number if they have not been dialed.

It must therefore be ensured that the emergency numbers 110 and 112 are always transmitted directly and unaltered to the outside world. This is automatically ensured in the easybell Cloud Telefonanlage.