There are four possible connections to the LX711: Ground (GND), Common (COM), Positive (POS), Negative (NEG). External devices can be connected to these four nodes via the color coded Banana Jacks. Various subsets of these nodes are also made available on the XLR-M and BNC connectors.

The GND node is the Chassis/Frame/Earth ground. The COM node is the floating/isolated common of the LX711 output circuitry. The POS and NEG nodes are the signal output pair, with one-half the signal amplitude appearing on each node relative to the common, and with opposite polarity.

The XLR-M connector provides connection to three nodes: GND(1), POS(2), and NEG(3). The BNC connector provides connection to the two signal nodes: POS(TIP) and NEG(SHD).

Two groups of 4-LED indicators provide status of the Output Mode and Output Impedance.

The four Output Modes are: Balanced, Unbalanced, Common Mode Input, and Common Mode Output. The Unbalanced mode connects the NEG node to GND.

The later two modes configure the output nodes in a special way to test the common mode performance of other balanced input and output devices. Common mode output tests are performed with a simple Y cable between the LX711, LX721, and other device.

The four Output Impedance selections are: 40 , 150, 600, or INF Ohms. The Infinite impedance selection leaves the POS and NEG signal outputs unconnected for open circuit testing without loading of other external devices.