When you have configured a CTI link in the Pega-call landing page, everything will be communicated in terms of events between Pega and the configured CTI link server. For example, upon logging into the Pega call application in the interaction portal a login event will get generated which would be observed in the browser console as JSON format. Every event which was sent by CTI link server will get converted to js events which in turn perform the necessary actions on the portal.
However, the question is about the network connection between a CTI Link Engine and a CTI Platform like for Avaya AES or Genesys T-Server. Should the network connection be bi-directional, that is, both CTI Link Engine and CTI Platform can initiate the data transmission?