Easy-to-use DBT100A and DBT300 handheld testers are able to quickly troubleshoot or test a MIL-STD-1553B Data Bus Network. These test units can detect shorts, opens, crossovers and shorts-to-shield on the bus and stubs. The testers are designed so the user can perform these checks from the Line Replaceable Unit (LRU) ends of the stub cables. In the DC resistance test modes, the tester functions as a general purpose ohmmeter with a range of 0 to 199.9 Ohms. The DBT300 adds the capability to measure Return Loss and Insertion Loss to easily benchmark network characteristics.