In 2011, the latest versions of IEC 60601-2-25 ed. 2.0, Electrocardiographs; and IEC 60601-2-27 ed. 3.0, Electrocardiographic Monitoring Equipment, were released. Both standards have the identical test for defibrillation protection, and they have been significantly revised from their previous versions for this test. A new switch, named S3 in the standard has been added, a resistor value has been changed from 470k to 390k, and the circuit topology has been changed, for the common mode test. For both common and differential mode tests, the test requires that the test pulses be delivered in a proscribed time period of 20 seconds between pulses. For the common mode test, five pulses of each polarity are delivered with 20 seconds between pulses. For the differential mode test, the test is repeated for each lead wire in turn, until all lead wires are tested.