Modular 4-terminal device for hobbyist and small-scale manufacture; input 12 V DC, output 86 V square wave, suited for ringing devices within 600 ohms of loop resistance (a mile or so on telephone wiring).  (A different ebay listing offers 5 Vin model.)

View the technical datasheet of this product and its engineering design manual Telecom Design Tricks on our company website as shown on the imaged label or receive this information by using the "contact seller" link.

This unit can be provided with its appropriate 12 Vdc adapter hardwired at time of shipment for a small additional charge by contacting seller at time of order.