From: www.electronic-supply.com 

Check this red-hot tool out.

159999 Model 50 TDR "Cable Fault Finder"

The model 50 TDR " Cable fault Finder"  provides contractors, electricians, low voltage installers, or anyone involved in the installation or maintenance of metallic cables with the capability to quickly find faults in cables up to a distance of 2500 feet. Simply select the appropriate cable type from the pre-stored library, attach the leads to two conductors of the cable and with a single press of a button the length of the cable or distance to an open or short is displayed. Voltage on the wires is continuously measured and displayed to warn of a potentially unsafe condition. The CableTool will also inject a tone onto the conductor for tracing cables installed in walls and ceilings with a standard tone probe. The universal banana jack test lead connectors allow for a wide range of adapters for any connector type. The affordable CableTool is an essential tool for anyone in the cabling industry. Download the CABLETOOL Brochure by clicking here.(1.3M PDF) Download the CABLETOOL User Guide by clicking here. (1.4M PDF) Technical Specifications Physical Characteristics Dimensions: 7.0 in. x 3.2 in. x 1.4 in. 178 mm x 81 mm x 36 mm Weight: 8.7 ounces (w/batteries) 247 grams Length Accuracy: +/-2% plus +/-2 ft. (with correct NVP) Resolution: 1 foot or 0.2 meters Maximum: 2500 feet Minimum: 0 feet Power Supply Four AA alkaline batteries (Included) Voltage (True RMS Responding) Range: 0-250V (AC or DC) Accuracy: +/-3% plus 1V Environment Operating Temperature: 0° to 50° C Storage Temperature: -10° to 55° C Tracing Tone Frequencies: 575Hz, 997Hz 1.0KHz, 7.82KHz Patterns: Four Display Graphical - 122 x 32 pixels Box Contents: 1 Cable Tool, 1 BNC Adapter, 1 "F" Coax Adapter, 2 Test Leads, 4 "AA" batteries, Case, and 1 Instruction Manual. PINPOINT CABLE DAMAGE Cables can be damaged during and after installation. Typically the damaged section is hidden from view behind walls, above ceilings or buried underground. The CABLE TOOL uses TDR (Time Domain Reflectometry) technology to quickly identify an open or a short and provide the distance to the problem location. Additionally, the tone generator feature works with standard tone probes so that the exact cable path can be traced. MEASURE CABLE LENGTH ON A SPOOL OR INSTALLED The CABLETOOL makes it easy for installers to know the amount of cable remaining on a spool or in a box before pulling a run. When multiple runs are being installed in the same area, the first run can be measured to accurately determine the total amount of cable required to complete the job. Checking cable inventory prior to starting a job eliminates unplanned trips to buy more cable. EASY TO USE The CABLETOOL is simple to operate. After turning the unit on, a cable can be measured or toned with a single push of a button. The full graphics display provides all the cable management information together on one screen. The built-in library of over sixty cable types makes finding the correct cable information easy. The standard banana jack connectors means that different test leads and adapters are available from many vendors. AFFORDABLE Telephone and CATV companies have used TDRs to find cable problems for over thirty years. Until recently, this type of tool cost thousands of dollars. Advances in technology have allowed the CABLETOOL to provide the capabilities of previous TDRs at a fraction of the price.

What is a TDR? Time Domain Reflectometer (TDR) is kind of a 'cable radar'. Like Radar, a signal is sent out, and the round-trip time from the TDR to the object of interest is measured. Our little hand-held TDR "Model 50" can detect a short or open (or the end of the piece of cable) in electrical transmission lines. For our purposes, we can consider a simple coaxial cable as being an electrical transmission line. Model 50 launches a signal into the cable. This signal takes a certain amount of time to travel down the cable. Upon reaching a short or an open in the cable, part of the signal is reflected back to the instrument. This information is then used to calculate the distance to the problem. (The time parameter is converted to distance since we know how fast the signal travels through the cable). Thus "Time Domain" means the time of the measured parameter, and "Reflectometry", indicates the instrumentation is looking for reflections from cable shorts or opens.