Yes, you´re right.

You take the DSC harness (as shown in the picture below) and connect the white wire to receiver DSC port and the other one with the aid of twin male wire to a free channel in the receiver.

I have done the same so that I took a spare extension cord and replaced the wires in the DSC harness with that. One wire to the DSC port and it works.

I do not use the DSC harness to charge the battery. I take the battery away during charging.

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