> For the complete documentation index, see [llms.txt](https://developer.magtek.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/dynaflex-ii-go/documentation/user-manuals/installation-and-operation-manual/user-interface/card-reading.md). # Card Reading ## **About Reading Cards** The steps for starting a transaction and reading a contactless payment device are different depending on the device’s configuration and on the design of the host software. Host software developers should see section 9 Developing Custom Software for implementation references. The solution developer should provide solution-specific instructions for operators to follow. A transaction generally follows this essential flow: * An advanced operator has already made sure DynaFlex II Go is configured properly and is connected to the host (see section 4.3 Connecting DynaFlex II Go to a Host). When the device is connected to the host and powered via the USB-C connector or internal rechargeable battery, the host software may keep a connection open to the device. * The operator makes sure DynaFlex II Go is receiving power either from the USB connection, or from the internal rechargeable battery, and is awake and powered on (see section 7.8.3) * The operator uses the host software’s user interface (for example, a point of sale) to finalize a transaction amount, then initiates a transaction. In solutions that are designed to respond to cardholder input events that occur when the device is idle, such as unprompted tapping of a card or electronic payment device, the host software may respond to those inputs by notifying the host. The host software may trigger other operations without being initiated by an operator (for example, the host software may immediately start a transaction, or alert the cardholder or operator to take action). * The host communicates with the device, and reports to the operator when the device is ready. * The operator guides and assists the cardholder in presenting payment. * The cardholder interacts with the device to present payment. The following sections provide additional details about presenting each of the available payment methods. * The host monitors the progress of the transaction, and when necessary, and should report issues to the operator, who may need to relay the messages to the cardholder. * The device reports the success or failure of the transaction to the cardholder and to the host. ## **How to Tap Contactless Cards / Devices** To tap a contactless card or smartphone, follow these steps: * Check LED status: * The device shows the transaction status using the LEDs. LED1 lights solid and all other LEDs are off, per EMV standards, to indicate it is ready for a tap. * All devices report detailed transaction status to the host, and host software may report that information to operators so they can guide cardholders through the transaction (for example, “please tap your card now”). * If the cardholder is using an electronic payment device, such as a smartphone, make sure the payment device has NFC turned On and has a payment app configured to process transactions. For details, see the documentation provided by the smartphone manufacturer and payment app publisher. * Briefly hold the card, smartphone, or other contactless payment device over the contactless landing zone, indicated by the EMVCo Contactless Indicator symbol on the device’s face (see Figure 7-28). Because each smartphone model may have its NFC antenna placed differently, the ideal tap position may vary by make and model. For example, Samsung users may need to center the phone on the contactless landing zone, while Apple users may need to tap the top of the phone on the contactless landing zone. * Wait for LED status: * The device quickly lights the second LED to show it is processing, then lights the third LED to show it has successfully read the tap, then lights the fourth LED to show the read is complete (see Figure 7-29) The device then returns to Ready State, when connected to USB ready state is LED 1 and 2 on only, ready state for BLE is LED 1,2, and 3 on. * The device beeps once. * If the transaction requires a signature, the device sends a notification message to the host that includes the status Signature Capture Requested. In this case, the solution design collects the cardholder’s signature manually or via a different method. * The device ends the transaction and reports the transaction status to the host. * If the device cannot communicate with the card, smartphone, or other contactless payment device: * The device ends the transaction. * The device lights LED 4 for a short time. * The device beeps twice. * The device notifies the host that the transaction failed. If this occurs, the host software may choose to retry the transaction or revert to prompting the operator to perform another operation that is specific to the solution design.

Figure - Tapping a Contactless Card / Smartphone

Figure – Contactless Read LED Sequence – Read Complete (Connected via Bluetooth® LE)

## **How to Scan Barcodes** To scan a barcode, follow these steps: * Make sure you are using a DynaFlex II Go model that includes a barcode reader, indicated by QR Code markings on the face of the device surrounding the barcode reader lens (see section 1.1 Key Features and Components). * If the barcode being scanned is not on a self-illuminated source such as a smartphone, make sure there is enough ambient light for the camera to read the barcode. In low light conditions, the barcode reader will only be able to read self-illuminated sources. * In some solutions, the operator may have to perform an operation in the host software to enable the barcode reader, or to start a transaction with the barcode reader enabled. * Wait for the device, the host, or the operator to prompt for a barcode read: * The device lights the barcode reader indicator LED next to the barcode reader lens. * Hold the barcode in front of the barcode reader camera: * If possible, use the light from the barcode reader indicator LED to align the barcode within the barcode reader’s field of view, which extends 16 degrees above / below and 21 degrees to the left/right of a line perpendicular to the barcode reader lens. * Hold the barcode as close as 6 inches from the lens. For smaller barcodes, the device will read immediately. If it does not, gradually move away up to 14 inches from the lens until the device reports a successful read. Larger barcodes must be far enough away from the device that the whole barcode is within the camera’s field of view; if a large barcode is too close, the barcode reader can only see a zoomed in portion of the barcode. * Do not tilt the barcode more than 60 degrees from parallel to the device’s face. * Wait for the device or the host to report the barcode has been read successfully: * The device beeps once. * The device turns off the barcode reader indicator LED.
## **Apple VAS for DynaFlex II Go** DynaFlex II Go products support Apple Value Added Services (Apple VAS) protocol. Contactless transactions using the Apple VAS protocol permits the device reader to perform the following supported operations: ## VAS App and Payment Mode (Dual Mode) The device reads both Apple VAS data and EMV payment data from a tapped smartphone or reads EMV payment data from a tapped card. When device sends ARQC to the host to conclude the transaction, it includes EMV payment data in container FC and includes VAS data, if available, in container FE ## VAS App Only Mode (VAS Mode) The device reads only Apple VAS data from a tapped smartphone and does not read data from a tapped card. If the tapped smartphone does not support VAS, the device does not detect or read from the smartphone. When the device sends ARQC to conclude the transaction, it includes VAS data in container FE and does not include EMV payment data in container FC. ## VAS App or Payment Mode (Single Mode) The device reads only Apple VAS data from a tapped smartphone or reads EMV payment data from a tapped card. When the device sends ARQC to conclude the transaction, it only includes either EMV payment data in container FC for cards, or includes VAS data in container for smartphones. ## Payment Only Mode (Payment Mode) The device operates the same as EMV mode (01). It reads only EMV payment data from a tapped smartphone or a tapped card. When the device sends ARQC to conclude the transaction, it includes EMV payment data in container FC and does not include VAS data in container FE. Note: THIS MODE MAY NOT BE NEEDED. For details, see *D998200597 DynaFlex II Go Programmer’s Manual (COMMANDS).* **1.1.1 How to Tap Contactless NFC Tags / MIFARE Classic / MIFARE DESFire /MIFARE Plus Cards and Send Pass-through Commands** DynaFlex II Go is compatible with near field communication (NFC) technology such as MIFARE Classic/MIFARE DESFire /MIFARE Plus contactless IC products (smart cards). To tap an NFC Contactless IC product and send pass-through commands, follow these steps: * Check LED status: * Per EMV standards, the device indicates transaction status through its LED indicators, located on the front face of the device. When ready for a tap, LED 1 is steadily illuminated while all other LEDs remain unlit. * All devices communicate transaction details to the host. The host software will relay this information to operators, allowing them to direct cardholders during the transaction, such as prompting "please tap your card now". * Place the card over the device's designated contactless landing zone, marked by the EMVCo Contactless Indicator symbol on the front face of the device. * Wait for LED status: * Initially, LED 2 illuminates, signaling the device is processing. The device subsequently illuminates LED 3 and LED 4, indicating card detection. Notifications are then sent to identify the card type and UID. * The Host application can further interact with the NFC Tag using pass-through commands. For details, see *D998200597 DynaFlex II Go Programmer’s Manual (COMMANDS).* * If the pass-through command is the last successful command, the device will end the transaction, emitting a single beep signaling a successful transaction. The user then needs to remove the card. * If an error is detected, the device will end the transaction and emit two beeps to signal the error. The user then needs to remove the card. * The device notifies the host that the transaction has ended with the NFC Tag removed. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://developer.magtek.com/hardware/card-readers/mms-dyna-devices/dynaflex-ii-go/documentation/user-manuals/installation-and-operation-manual/user-interface/card-reading.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.