Index: firmware/App/Modes/ModeSolo.c
===================================================================
diff -u -r200edfc2ef75cf499887b4c85d22264ded0db125 -rc48a99d2d1c852adcc986253b6c420a90dab7bfe
--- firmware/App/Modes/ModeSolo.c	(.../ModeSolo.c)	(revision 200edfc2ef75cf499887b4c85d22264ded0db125)
+++ firmware/App/Modes/ModeSolo.c	(.../ModeSolo.c)	(revision c48a99d2d1c852adcc986253b6c420a90dab7bfe)
@@ -1,4 +1,4 @@
-/**************************************************************************
+/**********************************************************************//**
  *
  *  Copyright (c) 2020 Diality Inc. - All Rights Reserved.
  *
@@ -18,46 +18,73 @@
 #include "ModeSolo.h"
 #include "CPLD.h"
 
+/**
+ *  @addtogroup SoloStandbyMode
+ *  @{
+ */
+
+// ********** private definitions **********
+
+/// Enumeration of solo standby mode states.
+typedef enum Solo_States
+{
+    SOLO_STANDBY_STATE_START = 0,                                       ///< Start solo standby mode state.
+    NUM_OF_SOLO_STANDBY_STATES                                          ///< Number of solo standby mode states.
+} SOLO_STANDBY_STATE_T;
+
 // ********** private data **********
 
+static SOLO_STANDBY_STATE_T soloState = SOLO_STANDBY_STATE_START;       ///< Currently active solo standby state.
+
 // ********** private function prototypes **********
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief
  * The initSoloMode function initializes the Standby-Solo Mode module.
  * @details
  * Inputs : none
  * Outputs : Standby-Solo Mode module initialized.
- * @param none
  * @return none
  *************************************************************************/
 void initSoloMode( void )
 {
+    soloState = SOLO_STANDBY_STATE_START;
 }
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief
  * The transitionToSoloMode function prepares for transition to standby-solo mode.
  * @details
  * Inputs : none
  * Outputs :
- * @param none
  * @return none
  *************************************************************************/
 void transitionToSoloMode( void )
 {
+    initSoloMode();
 }
 
-/*************************************************************************
+/*********************************************************************//**
  * @brief
  * The execSoloMode function executes the Standby-Solo Mode state machine.
  * @details
  * Inputs : none
  * Outputs :
- * @param none
  * @return none
  *************************************************************************/
 void execSoloMode( void )
 {
+    // execute current solo standby state
+    switch ( soloState )
+    {
+        case SOLO_STANDBY_STATE_START:
+            break;
 
+        default:
+            soloState = SOLO_STANDBY_STATE_START;
+            // TODO - s/w fault
+            break;
+    }
 }
+
+/**@}*/