Abstract: A chemical dispensing system controller is used in conjunction with a mechanism for dispensing specified chemicals and a device that transmits trigger signals to the control system for requesting chemicals to be dispensed. The controller receives and accumulates sequences of the transmitted trigger signals. Each trigger signal sequence is preceded and followed by a period of time of predefined duration during which no trigger signals are received. At least some of the trigger signals in some of the trigger signal sequences are not received simultaneously. Also, the number of distinct chemical feed requests that can be communicated using the accumulated trigger signals exceeds the number of distinct trigger signals. The controller maps a first subset of the accumulated trigger signal sequences into chemical feed requests, each of which requests a quantity of a corresponding chemical. The controller enables the dispensing of chemicals in accordance with the chemical feed requests.