Lg split inverter communication wire missing.

Hi.
I bought a second hand but never been used LG inverter split unit.
There is a quick connect 3 pin communication terminal on the indoor unit but no terminal and wires on the outdoor unit to connect it to.
I checkt outdoor units pc board and there is only a 4 pin and a 5 pin with no wires connected to them.
Anny help as to where it should be connected to?

Which model numbers are they? Indoor and outdoor.

Hi thanks for reply.
Outdoor is v12EUBo (ASUW126B1U0)
Indoor ASNH12GB7U0