Abstract: Provided is a channel status display for an X.25 wide area network (WAN) DTE-DCE interface. The invention, designed for use with a protocol analyzer, monitors X.25 level-2 frame traffic on the DTE-DCE link and produces a dynamic channel-activity-data-structure based upon the level-2 frames. An important class of level-2 frames are so-called I-frames. I-frames contain a 12-bit LCI (Logic Channel Identifier) field. The LCI number identifies up to 4095 channels over which network calls may be transmitted and received at the DTE-DCE interface. The LCI field of an I-frame is used to index an array of pointers. The pointers point to list members in a linked list of call-records. A call-record is a complete listing of call information for a given channel. The array of pointers and the linked list of call-records together make up the channel-activity-data-structure. The data-structure is updated with each new I-frame.