diff --git a/src/core/constants.js b/src/core/constants.js
index 948a4fa..62cb2c8 100644
--- a/src/core/constants.js
+++ b/src/core/constants.js
@@ -103,6 +103,7 @@ const serialProtocol = {
   sourceHost: 0xFF,       // SRC host/GUI
   endOfFrame: 0x0D,       // EOF
   addressAny: 0x00,       // DST = qualsiasi dispositivo (usato per discovery)
+  defaultDestinationAddress: 0x00, // DST UART usato da DataCOM: l'Addr del registro 1 e' il CAN Rx ID
   headerLength: 5,        // SOF + DST + SRC + 0x00 + DLEN
   tailLength: 3,          // CHK_HI + CHK_LO + EOF
   // Comandi (scritti nel registro 2)
diff --git a/src/core/reader.js b/src/core/reader.js
index 69c2b7c..5ee4565 100644
--- a/src/core/reader.js
+++ b/src/core/reader.js
@@ -74,6 +74,9 @@ class MPPTReader extends EventEmitter {
     // Buffer di ricezione e transazione pendente (protocollo sincrono: 1 alla volta)
     this.rxBuffer = Buffer.alloc(0);
     this.pendingTransaction = null;
+    // Indirizzo DST usato sul protocollo UART. Il registro Addr identifica il CAN Rx ID;
+    // DataCOM e il test Python interrogano l'MPPT con DST=0x00.
+    this.uartDestinationAddress = serialProtocol.defaultDestinationAddress;
 
     // Istanzia gli MPPT configurati (indicizzati per nome logico)
     this.mppts = new Map();
@@ -93,7 +96,8 @@ class MPPTReader extends EventEmitter {
     this.log(
       `[reader] configurazione: device=${this.device}, baudRate=${this.baudRate}, ` +
       `pollIntervalMs=${this.pollIntervalMs}, timeoutMs=${this.timeoutMs}, retries=${this.retries}, ` +
-      `dtr=${this.dtr}, rts=${this.rts}, mppts=${JSON.stringify(Array.from(this.mppts.values()).map((mppt) => ({
+      `dtr=${this.dtr}, rts=${this.rts}, uartDestinationAddress=${this.uartDestinationAddress}, ` +
+      `mppts=${JSON.stringify(Array.from(this.mppts.values()).map((mppt) => ({
         name: mppt.name,
         address: mppt.address,
       })))}`
@@ -263,7 +267,7 @@ class MPPTReader extends EventEmitter {
         for (const regAddr of pollRegisters) {
           try {
             this.log(`[reader] leggo MPPT ${mppt.name} address=${mppt.address} registro=${regAddr}`);
-            const rawValue = await this._readRegister(mppt.address, regAddr);
+            const rawValue = await this._readRegister(this.uartDestinationAddress, regAddr);
             this.log(`[reader] letto MPPT ${mppt.name} address=${mppt.address} registro=${regAddr} raw=${rawValue}`);
             mppt.updateRegister(regAddr, rawValue);
             updated = true;