diff --git a/JumperlessNano/src/MachineCommands.cpp b/JumperlessNano/src/MachineCommands.cpp
index 3ebcf3b..824a783 100644
--- a/JumperlessNano/src/MachineCommands.cpp
+++ b/JumperlessNano/src/MachineCommands.cpp
@@ -24,7 +24,7 @@ enum machineModeInstruction lastReceivedInstruction = unknown;
 
 char machineModeInstructionString[NUMBEROFINSTRUCTIONS][20] = {"unknown", "netlist", "getnetlist", "bridgelist", "getbridgelist", "lightnode", "lightnet", "getmeasurement", "gpio", "uart", "arduinoflash", "setnetcolor", "setnodecolor", "setsupplyswitch"};
 
-enum machineModeInstruction parseMachineInstructions(void)
+enum machineModeInstruction parseMachineInstructions(int *sequenceNumber)
 {
 
     int doneReading = 0;
@@ -55,17 +55,26 @@ enum machineModeInstruction parseMachineInstructions(void)
 
     char instructionBuffer[20] = {0};
 
+    int seqNumberSeparatorPos = -1;
+
     for (int i = 0; i < 20; i++)
     {
-        if (inputBuffer[i] == '[')
-        {
+        if (inputBuffer[i] == '[') {
             // inputBuffer[i] = ' ';
             break;
         }
+        if (inputBuffer[i] == ':') {
+          seqNumberSeparatorPos = i;
+        }
         instructionBuffer[i] = inputBuffer[i];
         inputBuffer[i] = ' ';
     }
 
+    if (seqNumberSeparatorPos > 0) {
+        instructionBuffer[seqNumberSeparatorPos] = 0;
+        *sequenceNumber = atoi(instructionBuffer + seqNumberSeparatorPos + 1);
+    }
+
     for (int i = 0; i < NUMBEROFINSTRUCTIONS; i++)
     {
         if (strcasecmp(instructionBuffer, machineModeInstructionString[i]) == 0)
@@ -107,6 +116,15 @@ enum machineModeInstruction parseMachineInstructions(void)
     return lastReceivedInstruction;
 }
 
+void machineModeRespond(int sequenceNumber, bool ok) {
+  Serial.print(ok ? "::ok" : "::error");
+  if (sequenceNumber >= 0) {
+        Serial.print(":");
+        Serial.print(sequenceNumber);
+  }
+  Serial.println("");
+}
+
 void machineNetlistToNetstruct(void)
 {
     char names[MAX_NETS][32] = {0};
diff --git a/JumperlessNano/src/MachineCommands.h b/JumperlessNano/src/MachineCommands.h
index 55dd785..7d8ad92 100644
--- a/JumperlessNano/src/MachineCommands.h
+++ b/JumperlessNano/src/MachineCommands.h
@@ -24,7 +24,8 @@ enum machineModeInstruction
 extern char inputBuffer[INPUTBUFFERLENGTH];
 extern char machineModeInstructionString[NUMBEROFINSTRUCTIONS][20];
 
-enum machineModeInstruction parseMachineInstructions(void);
+enum machineModeInstruction parseMachineInstructions(int *sequenceNumber);
+void machineModeRespond(int sequenceNumber, bool ok);
 void machineNetlistToNetstruct(void);
 void populateBridgesFromNodes(void);
 int nodeTokenToInt(char *);
diff --git a/JumperlessNano/src/main.cpp b/JumperlessNano/src/main.cpp
index d3db880..b58fc32 100644
--- a/JumperlessNano/src/main.cpp
+++ b/JumperlessNano/src/main.cpp
@@ -475,8 +475,8 @@ skipinput:
 
 void machineMode(void) // read in commands in machine readable format
 {
-  
-  enum machineModeInstruction receivedInstruction = parseMachineInstructions();
+  int sequenceNumber = -1;
+  enum machineModeInstruction receivedInstruction = parseMachineInstructions(&sequenceNumber);
 
   switch (receivedInstruction)
   {
@@ -545,9 +545,13 @@ void machineMode(void) // read in commands in machine readable format
 
   // case gpio:
   //   break;
+
+  case unknown:
+    machineModeRespond(sequenceNumber, false);
+    return;
   }
 
-  
+  machineModeRespond(sequenceNumber, true);
 }
 
 unsigned long logoFlashTimer = 0;