A room ionization system includes a plurality of emitter modules, each including an electrical ionizer. The emitter modules are spaced around the room and are connected in a daisy-chain manner to a system controller. Each emitter module has an individual address for allowing the system controller or a remote control transmitter to individually address and control each emitter module. Electrical lines containing both power and communication lines connect the plurality of emitter modules with the system controller. Each emitter module stores a balance reference value and an ion output current reference value for use by automatic balance control and automatic ion output current control circuitry. These reference values are stored in a software-adjustable memory so that they may be easily changed via the system controller or via the remote control transmitter if actual measured balance or decay times in the work space, such as measured by a charged plate monitor, indicate an ion imbalance or out of range ion output current. Each emitter module can send detailed alarm condition information and emitter module identification information to the system controller upon detection of a malfunction. Each emitter module connected to the system controller may be individually set to a desired operating power mode. The emitter modules use a switching power supply to lessen effects of line loss. Each emitter module includes miswire protection circuitry so that the electrical lines may be automatically flipped if initially connected in the reverse manner.