The difference between the DC-I and DC-C of the ground standard
Usually, we use the Direct Current in the Electric-Communication System. AC/DC power system outputs the -48V current which was connected to the equipments. And there are two kinds of the Grounding standard in the ITU-T K.27: DC-I (Isolated DC return) and DC-C (Common DC return).
If customer’s grounding system is DC-C, we should short connect the BGND and PGND with the sheet copper. If it is DC-I, we should remove the sheet copper between the BGND and PGND.
For some boards ( such as N1/N2PDU, R1EOW, Q2SAP, N1SCC ), they don’t support the DC-I power system. And if these boards are inserted into the DC-I system, these boards may be damaged.
Most of the countries are using the DC-C system, and for our equipments, we use the DC-C configuration by default. If the customer uses the DC-I power system, we need to remove the short-connection sheep copper between the BGND and PGND.