The LDB-3 Advanced Loop Detector monitors an analog phone line for ringing or an off hook condition. A built-in relay can be activated when either of these conditions are detected. This is ideal for monitoring line status or for providing a visual indication of such. The LDB-3Æs disable input is ideal for two-button emergency phones, such as VikingÆs E-1600-20A, allowing "Info" button calls to be placed without activating the relay (turning on the emergency strobe light, camera, etc.) Three DIP switches are provided for turning ring detection on or off, off-hook loop detection on or off and for selecting a ring cadence mode which allows the relay to follow ringing or to remain activated during the off time of standard ring cadence. The LDB-3 comes complete with a 12 VDC power adapter, and can also provide switched 12VDC .35 Amp output to power external lights, etc. during ringing and/or off-hook conditions. Features Include:Detects ring voltage and off hook loop current, On/off switches for ring detection and off hook/loop detection, Screw terminal connections, Selectable ring cadence mode (relay can remain on between rings), Wall mountable with foam tape (included) or screws (not included), Switched 12V DC output (follows relay activation for powering strobe lights, cameras, etc.), One set of (NO) normally open and (NC) normally closed relay contacts provided, Disable input, ideal for use with two-button emergency phones (E-1600-20A), will not activate relay on "Info" calls.