An LDAP to CardDAV phone book (1 way read) gateway for modern (business) phones.
Functional L2CPBG Diagram

Use case

Most modern (business) voice phones have the capability to do comfortable LDAP directory look-up like:

  • Directory search by alphabet letters
  • Reverse lookup for in- or out-bound calls
  • Reverse lookup by entering parts or the phone number

Unfortunately, most of the 'smaller' companies (i guess companies beyond 100 employee) don't have an 'enterprise' LDAP directory, much less than private persons.
Most of such companies do have something like a cloud address-book, often based on WebDAV / CardDAV (i.e. Nextcloud, Ownlcoud, Baïkal, Daylite, ...).
This is, where this gateway might make your live easier.
If this program get started on some kind of hardware (Linux, Windows, MacOS, Raspberry Pi, ...), it will do the following:

  1. Synchronize your CardDAV Server(s) to a small local database cache
  2. Answer on LDAP requests from your voice phone(s)
  3. Ask your local database cache for the LDAP requested phone-book entry
  4. Response with the matching CardDAV contacts, as LDAP results to your phone.


  • Query your CardDAV address book(s) by entering the alphabetic letters (or parts of the telephone number) in your (LDAP capable) phone (and dial one of the matching numbers).
  • Reverse lookup of inbound calls and display matching contact information on the phone.
  • Work with local formatted (non- E.164) CardDAV entered phone numbers like: '040-123456' or '001 807 1234567' as well as '+49 (0)40 1234567-8' = no need to format the phone numbers of your CardDAV contacts in a special notation.
  • Supports internal (extension) phone numbers.
  • Support dial prefix for external line.
  • Support short internal extension numbers.


Please check the Readme for detailed instructions.


License (tl;dr)

  • Closed source, binaries only
  • No warranty for anything
  • No liability for anything
  • Free but limited use for anybody (limited to approximately 12 requests per hour)
  • Commercial variant (with much higher or no limits)

License - EULA

3rd Party Licenses (acknowledgment)

Privacy Policy (tl;dr)

Privacy Policy "GDPR" (English)

Datenschutzerklärung "EU-DSGVO" (German)

Updated by Jörg Ebeling over 1 year ago · 35 revisions

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