The innovaphone PBX series are small hardware (or virtual systems) which are very powerful and customizable to almost all user requirements.
They also use Internet standard where ever possible.
For number reverse look up and address books, the preferred method is ldap.
In small installations you usually don't have your LDAP server configured to maintain all your contacts and phone numbers, so you are in fact missing a simple address book for your solution.
Of course there exist large ldap servers, like Estos Metadirectory and others, but for many use cases they are just oversized and too expensive.
This gap is now filled with the open source project "inno-thinyldap" which can be found on github.
It has two main functions:
- Forward and reverse look up of numbers against a built in mysql database
- Reverse look up of phone numbers against the tel.search.ch directory
The local mysql address book can be maintained by uploading/download xlsx file containing your contacts and phone numbers.
Give it a try and tell me what you think about it.
PS: If you need the same thing, but usable for hosting/multiple clients in the same installation, get in touch with firstname.lastname@example.org