A parameter upgrade system that uses an update tool that plugs into a sensor port of a physiological monitor so as to custom-configure the monitor's processor board with added physiological parameters, the parameter upgrade system comprising: a physiological monitor having a sensor port configured to attach and communicate with a sensor; a processor board in communications with the sensor port having a board digital signal processor; a plurality of firmware instructions residing on the processor board and executable by the board DSP so as to calculate a plurality of physiological parameters in response to a sensor signal received from the sensor; and a plurality of handheld upgrade tools (401, 405) individually attachable to the sensor port in lieu of the sensor so as to designate to the processor board which of the physiological parameters, if any, to calculate when the sensor is attached to the sensor port, wherein each of the plurality of handheld upgrade tools (401, 405) can be used to update processor board firmware and can be read via an external interface so that a user can determine the remaining number of upgrades for the each respective handheld upgrade tool, and wherein each of the plurality of handheld upgrade tools (401, 405) comprises: a tool DSP configured to read the available parameters from the processor board and, in response to determining a specific processor board parameter is unavailable on the processor board and determining the upgrade count is not zero, upgrade the unavailable processor board parameter by making it available on the processor board and decrement the tool upgrade count; a sensor port connector that mates directly with the sensor port and provides a communications path between the tool DSP and the board DSP; an I/O port connector that provides communications between the tool DSP and an external digital device; and an information element that identifies the handheld upgrade tool to the board DSP, wherein based on an attachment of a handheld upgrade tool of the plurality of upgrade tools to the sensor port, the processor board of the physiological monitor is configured to: read the information element to identify the handheld upgrade tool as one of the plurality of upgrade tools, once the handheld upgrade tool is identified as one of the plurality of upgrade tools, supply power to the handheld upgrade tool, and communicate with the tool DSP so as to identify a tool type of the handheld upgrade tool. a physiological monitor having a sensor port configured to attach and communicate with a sensor; a processor board in communications with the sensor port having a board digital signal processor; a plurality of firmware instructions residing on the processor board and executable by the board DSP so as to calculate a plurality of physiological parameters in response to a sensor signal received from the sensor; and a plurality of handheld upgrade tools (401, 405) individually attachable to the sensor port in lieu of the sensor so as to designate to the processor board which of the physiological parameters, if any, to calculate when the sensor is attached to the sensor port, wherein each of the plurality of handheld upgrade tools (401, 405) can be used to update processor board firmware and can be read via an external interface so that a user can determine the remaining number of upgrades for the each respective handheld upgrade tool, and wherein each of the plurality of handheld upgrade tools (401, 405) comprises: a tool DSP configured to read the available parameters from the processor board and, in response to determining a specific processor board parameter is unavailable on the processor board and determining the upgrade count is not zero, upgrade the unavailable processor board parameter by making it available on the processor board and decrement the tool upgrade count; a sensor port connector that mates directly with the sensor port and provides a communications path between the tool DSP and the board DSP; an I/O port connector that provides communications between the tool DSP and an external digital device; and an information element that identifies the handheld upgrade tool to the board DSP, wherein a tool DSP configured to read the available parameters from the processor board and, in response to determining a specific processor board parameter is unavailable on the processor board and determining the upgrade count is not zero, upgrade the unavailable processor board parameter by making it available on the processor board and decrement the tool upgrade count; a sensor port connector that mates directly with the sensor port and provides a communications path between the tool DSP and the board DSP; an I/O port connector that provides communications between the tool DSP and an external digital device; and an information element that identifies the handheld upgrade tool to the board DSP, wherein read the information element to identify the handheld upgrade tool as one of the plurality of upgrade tools, once the handheld upgrade tool is identified as one of the plurality of upgrade tools, supply power to the handheld upgrade tool, and communicate with the tool DSP so as to identify a tool type of the handheld upgrade tool.