Fiber communication is an important means of modern information transmission. The new transmission system, SDH, will be predominant in the Fiber communication through its incomparable strong point. SDH Receiver/Sender is one of the most important parts of SDH Fiber Optic Network. This article is to design and implement an automatic bench of SDH Testing. The bench provides TCL extended interface, so the testers can control the SDH process dynamically, and implement the automatic testing for SDH Receiver/Sender.

Among all the SDH test methods, traditional script-control test method is not only complex and hard to administrate, but also difficult to study, prone to fail, and poor to deal with mistakes. This article designs and implements a Tcl/TK software to control the process of SDH test. By encapsulating user's commands and using guide method in user graphic interface design, this software can simplify the process to deal with these commands and administrate the whole SDH test and provide a friendly Man-Machine conversation function. The software also is good at mistake-processing, which can handle the user's real-time operation mistake and give user corresponding information, and gain the efficiency for SDH tester.