# Frequently Asked Questions (FAQ) and Known Issues

### **About of Card Service**

#### &#x20;<mark style="color:red;">1-) Error on first card read after a chip transaction on x30TR/430TR</mark>

The **completeEmv** method must be executed after every chip transaction. This issue occurs if **completeEmv** is not performed when an error is encountered.

#### <mark style="color:red;">2-) The broadcast containing card data is received twice, which leads to duplicate transactions.</mark>

This issue is typically caused by the CardService being bound multiple times.

To resolve it, a control flag should be implemented in the broadcast handling logic to prevent re-entrance and block duplicate processing when the broadcast is received more than once.

#### <mark style="color:red;">**3-) Failure to read on-us cards during the card routing flow after trigger.**</mark>

When the application is launched through the **parameter\_action** trigger, the EMV configuration files must be explicitly initialized.

In this scenario, the **emv**\_**config.xml** and **emvcl**\_**config.xml** files are required to be set using the following APIs:

* **setEMVConfig()**
* **setEMVCLConfig()**

### **About of** KMS Service

#### <mark style="color:red;">**1-) 400TR/1000TR TR31 Key Block Key Inject Error**</mark>

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During the *completeKeyExchange* process, the TMK that is written must be defined as a **KBPK (Key Block Protection Key)**.

According to the key block structure, the *mode of use* for the **TPK (Terminal PIN Key)** must be set to **'E' (Encryption Only)**. Additionally, the *exportability* field must be set to **'N' (Non-exportable)**. This ensures that the PIN key is used strictly for encryption purposes and cannot be exported outside the secure cryptographic environment, in compliance with security standards.

#### <mark style="color:red;">**2-) Key Exchange 503 Error**</mark>

This error typically occurs when the **Complete Key Exchange** operation is executed even though the **Start Key Exchange** process has not been successfully completed.

When this error is encountered, the first step should be to verify whether the **Start Key Exchange** process has completed successfully.

### **About of Printer Service**

#### <mark style="color:red;">**1-) Failure to print logos on the receipt.**</mark>

This issue may occur if the logo is not in monochrome format.

To resolve this issue, you can verify whether the logo is in the correct format by using the **BitmapChecker.isMonochromeBitmap** function located in the **printerService** module. After confirming that the logo meets the required structure, you may proceed with printing your external bitmap.

### **About of Protocol**&#x20;

#### <mark style="color:red;">**1-) Failure to close receipt after power cut in foreign exchange transactions**</mark>

This error occurs because the **amount** value returned to the PGW within the intent after the **checkSaleReceiver** action contains the foreign currency amount.

The returned **amount** value should instead be the **original** **TL amount** received at the beginning of the transaction.