A PBX, or Private Branch Exchange, is a telephone system in an organization that switches calls between people in that organization on local lines while allowing them to share several external phone lines. In short, it allows Rock to talk to the phones within your organization. PBX CDR Records downloads phone call detail records for the calls made on those phones and stores them in interaction tables. This valuable data helps you map the real-life relationships that exist within your organization. It also allows you to use click-to-call technology, where Rock places your calls for you with the click of a button. You'll need a plug-in to let Rock talk to your phone system. You can write your own, or you can use one of the plugins available in the Rock Shop, such as Digium Switchvox. Additional PBX plugins will be added as this technology becomes more widely used.