Multiple-code oximeter calibration element

An oximeter probe encoding apparatus, comprising:

• first and second leads;
• a first encoding device comprising a resistor configured to produce a first code value in response to a first signal at a first time;
• and
• a second encoding device configured to produce a second code value at a second time in response to said first signal, said second encoding device comprising a thermistor arranged to switch between first and second resistive states after being heated by being provided a current for a period of time.

An oximeter probe encoding apparatus, comprising:

• first and second leads;
• an encoding device configured to produce a first code value at said first and second leads in response to an oximeter monitor applying a first signal to said first and second leads at a first time;
• and
• a capacitor coupled to said encoding device, wherein a charge on said capacitor changes in response to said oximeter monitor applying the first signal to said first and second leads, causing said encoding device to produce a second code value at said first and second leads at a second time.

An oximeter sensor encoding apparatus, comprising:

• first and second leads;
• a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when said first and second leads are driven with a DC signal provided by an oximeter monitor;
• and
• a second encoding element, coupled to said first encoding element, configured to produce a second code value at said first and second leads when said first and second leads are driven with an AC signal provided by said oximeter monitor;
• wherein said first and second encoding elements are configured to produce the same first code value regardless of the polarity of said DC signal.

An oximeter sensor encoding apparatus, comprising:

• first and second leads;
• a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when driven with a first voltage or current level applied by an oximeter monitor to said first and second leads at a first time;
• and
• a second encoding element, coupled to said first encoding element, configured to produce a second code value at said first and second leads when driven with a second voltage or current level applied by said oximeter monitor to said first and second leads at a second time;
• wherein said first and second encoding elements are configured to produce the same first code value regardless of the polarity of said first voltage or current level.

An oximeter sensor encoding apparatus, comprising:

• first and second leads;
• a first encoding device configured to provide a first encoded value across said first and second leads in response to a first signal applied by an oximeter monitor to said first and second leads;
• and
• a second encoding device configured to provide a second encoded value across said first and second leads in response to a control signal on a third lead from said oximeter monitor.

An oximeter probe encoding apparatus, comprising:

• a first lead;
• a second lead;
• a third lead;
• an encoding device configured to produce a first code value at said first and second leads in response to a first signal applied by an oximeter monitor to said first and second leads, said encoding device being configured to produce a second code value at said first and second leads in response to a second signal from said oximeter monitor, and said encoding device being configured to produce a third code value at said first and second leads.

An oximeter probe encoding apparatus, comprising:

• an LED driven by a drive current;
• first and second leads;
• a first encoding element coupled to said first and second leads, configured to produce a first code value at said first and second leads when driven with a first voltage or current level applied by an oximeter monitor to said first and second leads at a first time;
• and
• a second encoding element configured to produce a second code value at said first and second leads when driven with a second voltage or current level provided by said LED drive current at a second time.