We get a lot of questions about telephony in general and our integration of Asterisk and Bitrix24 in particular. One of the most common questions is: "How to add or remove a prefix to a phone number in order to bring all numbers to the same format?"
For starters, let's see why all numbers must be registered in the same format. The answer is simple: in order to tie CRM with PBX, it's necessary to unify the key point of contact between the two systems - the phone number. Otherwise Bitrix24 will not be able to compare numbers of incoming and outgoing calls.
Inbound
Various operators transmit phone numbers with various prefixes, for example, +7/7/8 or even without any prefix at all (4995555555). Thus by default the client's number is registered in the format set by the operator, for instance, without prefix 7. Because of that it might be impossible to call back your client since the operator receives outgoing calls only with prefix 7.
Furthermore a company may have several numbers and operators that are serving them. If a call comes from the same client but through different operators and his number is registered in various formats, the same client will be registered in the system as two (or more) different leads. For all interactions with the client to be registered in the same call entity, all phone numbers must be written in a unified format.
To do this you must manually set desirable prefix to all incoming numbers. You can do it with any third-party module, for example, Set CallerID.
Outbound
To set the number format for outgoing calls you need to check with your operator which requirements they have for the number format and depending on this either add or remove certain digits in our module. This parameter is set individually for each outbound route since the routes are tied usually either to various third-party equipment or to various operators.
FreePBX → Connectivity → Outbound Routes → Actions → Edit → Dial patterns → Prefix
Also it's important to pay attention to the fact that when a call goes through some third-party equipment, often it's necessary not only to unify but also to add certain prefixes.
Let's say you are in the A city and you want to call the B city number via local PBX. To do this you need to dial an additional digit but when transmitting data to Bitrix24 you need to remove it. In our module you can do it in a special section "Advanced settings", field "Number modification for Bitrix24".
FreePBX → Admin → InformUnity Bitrix24 → Outbound Routes → Actions → Edit → Advanced settings → Number Modification for Bitrix24
