Index: firmware/App/Drivers/ConductivityTeensy.h
===================================================================
diff -u -rfea37ad4659d4162d43f3e343cd5b266c2757ea9 -r4954a58fad7d100068baed367ae074ca6c132813
--- firmware/App/Drivers/ConductivityTeensy.h	(.../ConductivityTeensy.h)	(revision fea37ad4659d4162d43f3e343cd5b266c2757ea9)
+++ firmware/App/Drivers/ConductivityTeensy.h	(.../ConductivityTeensy.h)	(revision 4954a58fad7d100068baed367ae074ca6c132813)
@@ -68,6 +68,7 @@
     TEENSY_CMD_STOP_MEASUREMENT,                           ///< Maps to command "n"
     TEENSY_CMD_GET_ALL_MEASUREMENTS,                       ///< Maps to command "g"
     TEENSY_CMD_GET_SINGLE_MEASUREMENT,                     ///< Maps to command "h"
+    TEENSY_CMD_SELECT_SENSOR,                              ///< Maps to command "u"
     MAX_NUM_OF_TEENSY_CMDS                                 ///< Total number of commands
 } TEENSY_CMD_INDEX_T;
 
@@ -120,15 +121,40 @@
     COND_MST_STATUS_SUCCESS
 } COND_UPDATE_MST_STATUS_T;
 
+typedef enum Conductivity_Models
+{
+    STANDARD,                   // standard equation for conductivity
+    ALY_LINEAR,                 // Aly's high range model for conductivity
+    UPDATED_STANDARD,           // Updated stand equation with a linear transformation.
+    NUM_OF_MODELS,
+} COND_MODELS_T;
+
 /// Coefficients to be applied with raw impedance and rtd values to calculate conductivity and temperature.
+/// Coefficients stored into the EEPROM of the sensors contain values for more than one model and each subsystem.
 typedef struct
 {
-    F64 A0;
-    F64 A1;
-    F64 B0;
-    F64 B1;
-    F64 B2;
-    F64 B3;
+    F64 beta;                                   // Temperature scale factor, all models
+    F64 gamma;                                  // Temperature offset factor, all models
+    F64 kHighDDUS;                              // Cell constant, high range ( DD ), Updated standard
+    F64 alphaHighDDUS;                          // Temperature correction factor, high range (DD), Updated Standard
+    F64 etaHighDDUS;                            // Resistance scale factor, high range (DD), Updated Standard
+    F64 zetaHighDDUS;                           // Resistance offset, high range (DD), Updated Standard
+    F64 kLowFPS;                                // Cell constant, low range ( IOFP ), Standard
+    F64 alphaLowFPS;                            // Temperature correction factor, low range (IOFP), Standard
+    F32 kHighDDS;                               // Cell constant, high range (DD), Standard
+    F32 alphaHighDDS;                           // Temperature correction factor, high range (DD), Standard
+    F32 kLowFPUS;                               // Cell constant, low range (IOFP), Updated Standard
+    F32 alphaLowFPUS;                           // Temperature correction factor, low range (IOFP), Updated Standard
+    F32 etaLowFPUS;                             // Resistance scale factor, low range (IOFP), Updated Standard
+    F32 zetaLowFPUS;                            // Resistance offset, low range (IOFP), Updated Standard
+    F32 beta0DD;                                // Beta 0 (DD), Aly Linear
+    F32 beta1DD;                                // Beta 1 (DD), Aly Linear
+    F32 beta2DD;                                // Beta 2 (DD), Aly Linear
+    F32 beta3DD;                                // Beta 3 (DD), Aly Linear
+    F32 beta0FP;                                // Beta 0 (IOFP), Aly Linear
+    F32 beta1FP;                                // Beta 1 (IOFP), Aly Linear
+    F32 beta2FP;                                // Beta 2 (IOFP), Aly Linear
+    F32 beta3FP;                                // Beta 3 (IOFP), Aly Linear
 } COND_COEFF_T;
 
 ///  Structure to receive Sensor Measurement data from Teensy
@@ -174,6 +200,7 @@
 typedef struct
 {
     F64 Conductivity;
+    F64 Resistance;
     F64 Temperature;
 } COND_CALCULATED_MEASUREMENTS_T;