diff --git a/poc-datacollector/modules/ROOT/pages/doc-readmongo_service.adoc b/poc-datacollector/modules/ROOT/pages/doc-readmongo_service.adoc
index ccf13c5..de69a33 100644
--- a/poc-datacollector/modules/ROOT/pages/doc-readmongo_service.adoc
+++ b/poc-datacollector/modules/ROOT/pages/doc-readmongo_service.adoc
@@ -42,6 +42,57 @@ async function onCollectionNew(err, collection) {
 
 ----
 
+  var cursor = collection.find({}, options).stream();
+
+A Tailable Cursor *remains open* after the client exhausts the results in the initial cursor. 
+
+Tailable cursors are conceptually equivalent to the *tail* Unix command with the *-f* option (i.e. with "follow" mode). 
+
+After clients insert new additional documents into a capped collection, the tailable cursor will continue to retrieve documents.
+
+
+=== socket (open,event)
+
+[source,javascript]
+----
+
+io.on("connection", (s) => {
+  console.error("socket connection");
+  var usersession = new Object();
+  usersession.SOCKET = {};
+  usersession.SOCKET.error = {};
+  console.error("socket ...");
+  s.auth = false;
+
+  // ------------------------------
+  // --- authenticate
+  // ------------------------------
+  s.on("authenticate", function (data) {
+    const token = data;
+    (async () => {
+      var isvalid = await checkToken(token);
+      if (isvalid.action == "ok") {
+        usersession.SOCKET.user = isvalid.user;
+        usersession.SOCKET.scope = isvalid.scope; // space delimeter
+        usersession.SOCKET.token = isvalid.token;
+        usersession.SOCKET.id = s.id;
+        s.auth = true;
+      } else {
+        s.auth = false;
+      }
+    })();
+  });
+
+  // ------------------------------
+  // --- event
+  // ------------------------------
+  s.on("onevent", function (data) {
+    var binddata = {
+      user: data,
+      id: s.id,
+    };
+----
+
 
 === restart