Index: firmware/App/Services/SystemCommMessages.c
===================================================================
diff -u -r054fa08b67ed2a31f7848b179fbcd1b4da501b0f -r744b177ec4114c62303e976aed1677b820f7a281
--- firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 054fa08b67ed2a31f7848b179fbcd1b4da501b0f)
+++ firmware/App/Services/SystemCommMessages.c	(.../SystemCommMessages.c)	(revision 744b177ec4114c62303e976aed1677b820f7a281)
@@ -99,14 +99,6 @@
 {
     F32 volume_mL;
     UF_ADJ_T adjustType;
-} UF_SETTINGS_CHANGE_REQ_PAYLOAD_T;
-
-typedef struct
-{
-    BOOL confirmed;
-    F32  volume_mL;
-    U32  treatTime_min;
-    F32  uFRate_mL_min;
 } UF_SETTINGS_CHANGE_CONFIRMATION_PAYLOAD_T;
 
 #pragma pack(pop)
@@ -415,13 +407,13 @@
 {
     BOOL result = FALSE;
 
-    if ( message->hdr.payloadLen == sizeof(UF_SETTINGS_CHANGE_REQ_PAYLOAD_T) )
+    if ( message->hdr.payloadLen == sizeof(U32) )
     {
-        UF_SETTINGS_CHANGE_REQ_PAYLOAD_T payload;
+        U32 uFVolume;
 
-        memcpy( &payload, message->payload, sizeof(UF_SETTINGS_CHANGE_REQ_PAYLOAD_T) );
+        memcpy( &uFVolume, message->payload, sizeof(U32) );
 
-        result = verifyUFSettingsChange( payload.volume_mL, payload.adjustType );
+        result = verifyUFSettingsChange( uFVolume );
     }
     sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_HD_2_UI, result );
 }
@@ -495,7 +487,7 @@
 
         memcpy( &payload, message->payload, sizeof(UF_SETTINGS_CHANGE_CONFIRMATION_PAYLOAD_T) );
 
-        result = verifyUFSettingsConfirmation( payload.confirmed, payload.volume_mL, payload.treatTime_min, payload.uFRate_mL_min );
+        result = verifyUFSettingsConfirmation( payload.volume_mL, payload.adjustType );
     }
     sendAckResponseMsg( (MSG_ID_T)message->hdr.msgID, COMM_BUFFER_OUT_CAN_HD_2_UI, result );
 }
@@ -527,6 +519,46 @@
 
 /*************************************************************************
  * @brief
+ * The sendChangeTreatmentDurationResponse function constructs a treatment \n
+ * duration change response to the UI and queues the msg for transmit on the \n
+ * appropriate CAN channel.
+ * @details
+ * Inputs : none
+ * Outputs : treatment duration change settings response msg constructed and queued.
+ * @param accepted : alarm status record
+ * @param reason : reason rejected (if not accepted)
+ * @param time_min : alarm status record
+ * @param volume_mL : alarm status record
+ * @return TRUE if msg successfully queued for transmit, FALSE if not
+ *************************************************************************/
+BOOL sendChangeTreatmentDurationResponse( BOOL accepted, U32 reason, U32 time_min, F32 volume_mL )
+{
+    BOOL result;
+    F32 volume_L = volume_mL / (F32)ML_PER_LITER;
+    MESSAGE_T msg;
+    U08 *payloadPtr = msg.payload;
+
+    // create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_USER_TREATMENT_TIME_CHANGE_RESPONSE;
+    msg.hdr.payloadLen = sizeof( BOOL ) + sizeof( U32 ) + sizeof( U32 ) + sizeof( F32 );
+
+    memcpy( payloadPtr, &accepted, sizeof( BOOL ) );
+    payloadPtr += sizeof( BOOL );
+    memcpy( payloadPtr, &reason, sizeof( U32) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &time_min, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &volume_L, sizeof( F32 ) );
+
+    // serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    result = serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_UI, ACK_REQUIRED );
+
+    return result;
+}
+
+/*************************************************************************
+ * @brief
  * The handleChangeBloodDialysateRateChangeRequest function handles a blood \n
  * and dialysate rate settings change message from the UI.
  * @details
@@ -594,6 +626,50 @@
 
 /*************************************************************************
  * @brief
+ * The sendTreatmentParamsRangesToUI function constructs a treatment parameter \n
+ * ranges message to the UI and queues the msg for transmit on the appropriate CAN channel.
+ * @details
+ * Inputs : none
+ * Outputs : Treatment parameter ranges msg constructed and queued.
+ * @param minTime : Minimum treatment duration (in minutes).
+ * @param maxTime : Maximum treatment duration (in minutes).
+ * @param minUFVol : Minimum ultrafiltration volume (in mL).
+ * @param maxUFVol : Maximum ultrafiltration volume (in mL).
+ * @param minDialRate : Minimum dialysate flow rate (in mL/min).
+ * @param maxDialRate : Maximum dialysate flow rate (in mL/min).
+ * @return TRUE if msg successfully queued for transmit, FALSE if not
+ *************************************************************************/
+BOOL sendTreatmentParamsRangesToUI( U32 minTime, U32 maxTime, U32 minUFVol, U32 maxUFVol, U32 minDialRate, U32 maxDialRate )
+{
+    BOOL result;
+    MESSAGE_T msg;
+    U08 *payloadPtr = msg.payload;
+
+    // create a message record
+    blankMessage( &msg );
+    msg.hdr.msgID = MSG_ID_TREATMENT_PARAM_CHANGE_RANGES;
+    msg.hdr.payloadLen = sizeof( U32 ) + sizeof( U32 ) + sizeof( U32 ) + sizeof( U32 ) + sizeof( U32 ) + sizeof( U32 );
+
+    memcpy( payloadPtr, &minTime, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &maxTime, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &minUFVol, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &maxUFVol, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &minDialRate, sizeof( U32 ) );
+    payloadPtr += sizeof( U32 );
+    memcpy( payloadPtr, &maxDialRate, sizeof( U32 ) );
+
+    // serialize the message (w/ sync, CRC, and appropriate CAN padding) and add serialized message data to appropriate comm buffer
+    result = serializeMessage( msg, COMM_BUFFER_OUT_CAN_HD_2_UI, ACK_REQUIRED );
+
+    return result;
+}
+
+/*************************************************************************
+ * @brief
  * The sendDialysateTempTargetsToDG function constructs a dialysate temperature \n
  * set points message for DG and queues the msg for transmit on the appropriate CAN channel.
  * @details