English to French Tech/Engineering Electronics / Elect Eng

This is in the context of a power meter manual. I wonder if here i have to translate with "biais" or with "polarisation". The sentence is "Controls the biasing option on the RS485 bus". Other occurences of "bias" in this manual are: "Use the RS485 Bias setting to fine-tune RS-485 communications" and "Set bias to ON when the meter is acting as Master on that port, and leave it OFF when the meter is a Slave". Thanks!