EDAS supports TPC email discussions for a paper. TPC members and reviewers can click on the icon at the bottom of the paper page to add a note to the paper discussion. The note is then distributed by email. There is no special configuration option needed to enable these discussions, but you can determine who receives copies of the discussion messages by email via the template configuration. The Conference:Reviews configuration setting TPC discussion determines whether messages are sent anonymously, i.e., without identifying the discussant, or with the name of person making the comment.
There is no time limit to the discussion phase. The conference needs to be configured to allow access to the discussion to various roles such as track chairs or session chairs, using the "read review discussion" permission in Conference:Configure, Permissions.