Yeastar- Avaya J series Handsets Contact directory
The J series will have to be set to use Company Contacts via Yeastar LDAP
In Yeastar Admin, enable LDAP
If you haven't provisioned the handsets yet, they will be enabled for LDAP on provisioning.

If you have already provisioned the handsets and they are active, you will have to factory default the handsets to pull new config file.