diff --git a/DCC.cpp b/DCC.cpp
index d573985..e7ca624 100644
--- a/DCC.cpp
+++ b/DCC.cpp
@@ -221,6 +221,22 @@ const ackOp PROGMEM WRITE_BIT1_PROG[] = {
      FAIL  // callback (-1)
 };
 
+const ackOp PROGMEM VERIFY_BIT0_PROG[] = {
+     BASELINE,
+     V0, WACK,  // validate bit is 0 
+     ITC0,      // if acked, callback(0)
+     V1, WACK,  // validate bit is 1
+     ITC1,       
+     FAIL  // callback (-1)
+};
+const ackOp PROGMEM VERIFY_BIT1_PROG[] = {
+     BASELINE,
+     V1, WACK,  // validate bit is 1 
+     ITC1,      // if acked, callback(1)
+     V0, WACK, 
+     ITC0,
+     FAIL  // callback (-1)
+};
 
 const ackOp PROGMEM READ_BIT_PROG[] = {
      BASELINE,
@@ -239,6 +255,30 @@ const ackOp PROGMEM WRITE_BYTE_PROG[] = {
       FAIL        // callback (-1)
       };
       
+const ackOp PROGMEM VERIFY_BYTE_PROG[] = {
+      BASELINE,
+      VB,WACK,     // validate byte 
+      ITCB,       // if ok callback value
+      STARTMERGE,    //clear bit and byte values ready for merge pass
+      // each bit is validated against 0 and the result inverted in MERGE
+      // this is because there tend to be more zeros in cv values than ones.  
+      // There is no need for one validation as entire byte is validated at the end
+      V0, WACK, MERGE,        // read and merge first tested bit (7)
+      ITSKIP,                 // do small excursion if there was no ack
+        SETBIT,(ackOp)7,
+        V1, WACK, NAKFAIL,    // test if there is an ack on the inverse of this bit (7)
+        SETBIT,(ackOp)6,      // and abort whole test if not else continue with bit (6)
+      SKIPTARGET,
+      V0, WACK, MERGE,        // read and merge second tested bit (6)
+      V0, WACK, MERGE,        // read and merge third  tested bit (5) ...
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      V0, WACK, MERGE,
+      VB, WACK, ITCB,  // verify merged byte and return it if acked ok 
+      FAIL };
+      
       
 const ackOp PROGMEM READ_CV_PROG[] = {
       BASELINE,
@@ -268,6 +308,7 @@ const ackOp PROGMEM LOCO_ID_PROG[] = {
       SETCV,(ackOp)29,
       SETBIT,(ackOp)5,
       V0, WACK, ITSKIP,  // Skip to SKIPTARGET if bit 5 of CV29 is zero
+      V1, WACK, NAKFAIL, // fast fail if no loco on track
       // Long locoid  
       SETCV, (ackOp)17,       // CV 17 is part of locoid
       STARTMERGE,
@@ -329,6 +370,16 @@ void DCC::writeCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback,
   else ackManagerSetup(cv, bitNum, bitValue?WRITE_BIT1_PROG:WRITE_BIT0_PROG, callback, blocking);
 }
 
+void  DCC::verifyCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking)  {
+  ackManagerSetup(cv, byteValue,  VERIFY_BYTE_PROG, callback, blocking);
+}
+
+
+void DCC::verifyCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking)  {
+  if (bitNum >= 8) callback(-1);
+  else ackManagerSetup(cv, bitNum, bitValue?VERIFY_BIT1_PROG:VERIFY_BIT0_PROG, callback, blocking);
+}
+
 
 void DCC::readCVBit(int cv, byte bitNum, ACK_CALLBACK callback, bool blocking)  {
   if (bitNum >= 8) callback(-1);
diff --git a/DCC.h b/DCC.h
index f62feb2..05e9f9e 100644
--- a/DCC.h
+++ b/DCC.h
@@ -81,6 +81,8 @@ class DCC {
   static void  readCVBit(int cv, byte bitNum, ACK_CALLBACK callback, bool blocking=false);  // -1 for error
   static void writeCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking=false) ;
   static void writeCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking=false);
+  static void verifyCVByte(int cv, byte byteValue, ACK_CALLBACK callback, bool blocking=false) ;
+  static void verifyCVBit(int cv, byte bitNum, bool bitValue, ACK_CALLBACK callback, bool blocking=false);
   
   static void getLocoId(ACK_CALLBACK callback, bool blocking=false);
 
diff --git a/DCCEXParser.cpp b/DCCEXParser.cpp
index 8a13c58..b34698d 100644
--- a/DCCEXParser.cpp
+++ b/DCCEXParser.cpp
@@ -221,11 +221,19 @@ void DCCEXParser::parse(Print * stream,  byte *com, bool blocking) {
         DCC::writeCVByte(p[0],p[1],callback_W,blocking);
         return;
 
+    case 'V':      // VERIFY CV ON PROG <V CV VALUE> <V CV BIT 0|1>
+        if (!stashCallback(stream,p)) break;
+        if (params==2) DCC::verifyCVByte(p[0],p[1],callback_Vbyte,blocking);
+        else if (params==3) DCC::verifyCVBit(p[0],p[1],p[2],callback_Vbit,blocking);
+        else break;
+        return;
+
     case 'B':      // WRITE CV BIT ON PROG <B CV BIT VALUE CALLBACKNUM CALLBACKSUB>
         if (!stashCallback(stream,p)) break; 
         DCC::writeCVBit(p[0],p[1],p[2],callback_B,blocking);
         return;
         
+        
     case 'R':     // READ CV ON PROG <R CV CALLBACKNUM CALLBACKSUB>
         if (!stashCallback(stream,p)) break;
         DCC::readCV(p[0],callback_R,blocking);
@@ -510,6 +518,15 @@ void DCCEXParser::callback_B(int result) {
         StringFormatter::send(stashStream,F("<r%d|%d|%d %d %d>"), stashP[3],stashP[4], stashP[0],stashP[1],result==1?stashP[2]:-1);
         stashBusy=false;
 }
+void DCCEXParser::callback_Vbit(int result) {        
+        StringFormatter::send(stashStream,F("<v %d %d %d>"), stashP[0], stashP[1],result);
+        stashBusy=false;
+}
+void DCCEXParser::callback_Vbyte(int result) {        
+        StringFormatter::send(stashStream,F("<v %d %d>"), stashP[0],result);
+        stashBusy=false;
+}
+
 void DCCEXParser::callback_R(int result) {        
         StringFormatter::send(stashStream,F("<r%d|%d|%d %d>"),stashP[1],stashP[2],stashP[0],result);
         stashBusy=false;
diff --git a/DCCEXParser.h b/DCCEXParser.h
index 9067340..a90e1b4 100644
--- a/DCCEXParser.h
+++ b/DCCEXParser.h
@@ -55,6 +55,8 @@ struct DCCEXParser
     static void callback_W(int result);
     static void callback_B(int result);        
     static void callback_R(int result);
+    static void callback_Vbit(int result);
+    static void callback_Vbyte(int result);
     static FILTER_CALLBACK  filterCallback;
     static void funcmap(int cab, byte value, byte fstart, byte fstop);