When recording any of these signals, it is important to properly connect the ground from the logic analyzer to either the ground of the transmitter or the receiver. Do not connect ground to one of the signal wires, as this could damage your equipment. Neither RS-232, RS-485, nor RS-422 are isolated, which means that all transmitters and receivers on the bus must share the same ground to operate. In most cases, a ground wire is included in the bus wiring, which could be tapped with Logic. Otherwise, you will need to find another ground connection nearby to connect to.