In order to create the routing settings in your PBX correctly, you need to know in which format your phone number is signaled.

You have three different options to choose from in your easybell customer portal, which you can switch in the number management via "Number signaling".

We would like to briefly explain the modes:

1. E.164-Format

Default for merged accounts and extensions of number blocks (DDI)

With the E.164 format, the international dialing code is specified without leading zeros (example 493012345).

If you use the E.164 format, the information for call number signaling is taken from the SIP-Invite. Here the complete dialed phone number is stored in the TO: header in E.164, i.e. without leading zeros.

2. E.164 format with leading "+"

Standard for 3CX telephone systems

Some pbxes, including the 3CX, expect signalling in E.164 format with a leading plus sign.

Similar to the E.164 standard without a plus sign, the information for number signalling is taken from the SIP invite.

The E.164 formats are easier to process for most pbxes and allow more precise routing than the international format, for example.

We therefore strongly recommend using one of the two available E.164 formats instead of the international format.

3. International format

Default for trunks and single phone numbers, as well as virtual DDIs

In the so-called international format, there are two zeros before the country code. For example 00493012345.

If you choose to use the international mode, the information to be signaled is taken from the so-called Contact header. This is automatically transmitted when a SIP trunk is registered and may be configured freely.

Rufnummernformat umschalten

Sie können das Rufnummernformat für jede Rufnummer bzw. jeden Trunk individuell anpassen. Diese geschieht wie gewohnt in der Rufnummernverwaltung.

Hier gibt es eine detaillierte Anleitung dazu: „Link“.

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Created on: 22. June 2026