A radio frequency, RF, system comprising: a first RF generator having a first digital communication port and connected to a first electrode of a load and configured to generate a first RF signal to the first electrode; a second RF generator having a second digital communication port and connected to a second electrode of the load and configured to generate a second RF signal to the second electrode, wherein the first and second RF generators (12, 14) are configured to provide a respective RF voltage to the first and second electrodes (32, 40); and a controller configured to control the second RF generator, and to generate a control signal to at least one of the first RF generator or the second RF generator; wherein the first digital communication port and the second digital communication port are connected, and the first RF generator and the second RF generator are configured to communicate via the first digital communication port and the second digital communication port; wherein the second RF generator is configured to communicate a request to the first RF generator via the second digital communication port to request adjustment of the second RF signal, and the first RF generator is configured to vary a RF control signal applied to the second RF generator to adjust the second RF signal; and wherein the first RF generator and the second RF generator are configured to operate at substantially a same frequency in accordance with a RF control signal communicated from the first RF generator to the second RF generator. a first RF generator having a first digital communication port and connected to a first electrode of a load and configured to generate a first RF signal to the first electrode; a second RF generator having a second digital communication port and connected to a second electrode of the load and configured to generate a second RF signal to the second electrode, wherein the first and second RF generators (12, 14) are configured to provide a respective RF voltage to the first and second electrodes (32, 40); and a controller configured to control the second RF generator, and to generate a control signal to at least one of the first RF generator or the second RF generator; wherein the first digital communication port and the second digital communication port are connected, and the first RF generator and the second RF generator are configured to communicate via the first digital communication port and the second digital communication port; wherein the second RF generator is configured to communicate a request to the first RF generator via the second digital communication port to request adjustment of the second RF signal, and the first RF generator is configured to vary a RF control signal applied to the second RF generator to adjust the second RF signal; and wherein the first RF generator and the second RF generator are configured to operate at substantially a same frequency in accordance with a RF control signal communicated from the first RF generator to the second RF generator. wherein the first digital communication port and the second digital communication port are connected, and the first RF generator and the second RF generator are configured to communicate via the first digital communication port and the second digital communication port; wherein the second RF generator is configured to communicate a request to the first RF generator via the second digital communication port to request adjustment of the second RF signal, and the first RF generator is configured to vary a RF control signal applied to the second RF generator to adjust the second RF signal; and wherein the first RF generator and the second RF generator are configured to operate at substantially a same frequency in accordance with a RF control signal communicated from the first RF generator to the second RF generator.