A transmitter may map, using a selected modulation constellation, each of C\u2032 bit sequences to a respective one of C\u2032 symbols, where C\u2032 is a number greater than one. By spatially resolving the interference, an image of the spatial beat pattern between two modes may be constructed, thereby providing information about the modes supported by the optical fiber. The portion of the web page includes a selector allowing the user to concurrently select respective values for two or more dimensions. Each block dictionary may include a list of block identifiers, where each block identifier is associated with a value identifier and there is a block identifier for each unique value in a block. The identification numbers and labels are cross-linked with stored references which are used to dynamically generate HTML links. The operator interface is capable of receiving additional information that enables the operation of the control unit in at least one of the at least two modes.