Features:Detection and Lockout of Data Services: T-1, E1, ISDN (BRI xDSL Filters and PRI), SW56, ADSL, HDSL, VDSLDigital circuit safetyVoltage alarm and Lock-outLoudspeaker listeningVolume controlMicrophone muteTalk/Monitor status LEDBattery low audible toneTone/ pulse diallingRedial (10x24 digit memories)Super Hi Impedance polaritySuper Hi Impedance monitorHigh monitor levelSelectable ringer tonesHigh impact resistanceHigh chemical resistanceReplaceable premium cordsetEasy shoulder placementUnique glass reinforced nylon quick release belt clipIn today's evolving world of communications, technicians encounter an ever increasing amount of data on copper lines. Whether installing, servicing or simply maintaining voice service, the technician must consider the possible presence of digital traffic. Tempo's DigAlert™ 350 Test Sets offer the latest in data protection, allowing technicians to test the POTS service on a live ADSL line without fear of bringing down the data service.With this innovative design, Tempo set, unmatched standards in both quality and customer satisfaction. Test sets give meaning to the term "weatherproof" with an award-winning, waterproof case design that allows technicians to operate with confidence in even the most extreme weather conditions. Other key advancements include a high-voltage alarm and a quick release, non-metallic belt clip composed of Verton® RF, a strong, lightweight structural composite. This combination of rugged technology enables.In addition to all the features of the A340 range, D350 offers DigAlert digital services detection and lockout. Warning the user automatically if they attempt to go off-hook on a line that could be carrying a digital service. This lockout can be quickly overridden if needed.Digital Services Protection - In the "on hook" mode, on connection to a circuit, the Test Telephone sounds an alarm to alert the user to the presence of voltages above 75V to 80V DC. Such voltages are normally present on circuits carrying digital services. If the circuit is active, the user can select the high impedance MONITOR mode and listen to the sound to determine if the circuit is carrying digital services without disrupting the traffic. This is present in all models and can be overridden if the extended voltage is expected. If the unit detects a voltage above 120 V DC, this sounds a different alarm and cannot be overridden as this is definitely not a POTS line.The DigAlert™ Digital Services Detection and Lockout feature present in D350 and D361 models adds another layer of protection for digital services carried on telephony twisted pairs. Detecting "out-of-band" signals and preventing immediate "off-hook" this helps ensure that users of digital services are disrupted as little as possible during maintenance works. Effectively preventing the old practice of "tag running" and helping to ensure technicians only go "off-hook" when they need to. The high impedance monitor and polarity test, plus built-in xDSL blocking filter help to minimize in service errors that may occur to the DSL service.