The DS1202 is powered through its power jack. The power jack of the DS1202 accepts "small" power connectors with 3.5mm diameter. Use APR-P0011, APR-P0012, or APR-P0013 power adaptor supplied by Tibbo or similar adaptor with 12V nominal output voltage. Adaptor current rating should be at least 500mA. On the power jack, the ground is "on the outside", as shown on the figure below.