VDL Mode 3 Protocol Analyzer:

 

The VDL Mode 3 Protocol Analyzer (VPA) is a T1 line monitoring device that enables the capture and logging of VDL3 Mode 3 High Level Data Link Control (HDLC) messages. Unlike typical T1 test equipment, the VPA captures the VDL Mode 3 timing information in T1 slots 1 and 2 at the beginning of each HDLC transmission. This additional information allows NEXCOM system developers and testers the opportunity to validate message timing and to troubleshoot system communication problems.

The VPA captures HDLC messages on the RIU-MDR link and prints comma-delimited, ASCII formatted messages to the Terminal Interface. A separate computer running a terminal emulation package (such as HyperTerminal) can be configured to capture the ASCII messages to a file for subsequent analysis. A single-character command set enables set-up and control of the VPA. The VPA is designed to be installed INLINE between the MDR and RIU.

The VPA includes internal bridge circuitry to “tap” the line in both directions and also internally connects the two ports. In addition to the Terminal Interface, indicator LEDs are provided on the box for status of activity or errors.
 

CIE Engineering, Inc. • 6001 Woodlake Lane • Alexandria, VA 22315 • Phone: (703) 922-7061