The text in a frame can be independent of other frames, or it can flow between connected frames. To flow text between connected frames (also called text boxes), you must first connect the frames. Connected frames can be on the same page or spread, or on another page in the document. The process of connecting text among frames is called threading text. It is also referred to as linking text frames or linking text boxes.
Each text frame contains an in port and an out port, which are used to make connections to other text frames. An empty in port or out port indicates the beginning or end of a story, respectively. An arrow in a port indicates that the frame is linked to another frame. A red plus sign (+) in an out port indicates that there is more text in the story to be placed but no more text frames in which to place it. This remaining unseen text is called overset text.