This object indicates the power supply classification of the ONT Ethernet port. Options: 1. undefined(1) - Indicates that the actual power classification of the PD is undefined or the PD does not support the feature. 2. class0(2) - Indicates that the actual power classification of the PD is class 0. 3. class1(3) - Indicates that the actual power classification of the PD is class 1. 4. class2(4) - Indicates that the actual power classification of the PD is class 2. 5. class3(5) - Indicates that the actual power classification of the PD is class 3. 6. class4(6) - Indicates that the actual power classification of the PD is class 4. 7. invalid(-1) - Indicates that the query fails or no information is detected.