[Home](./index.md) > [@digitalpersona/devices](./devices.md) > [CardsReader](./devices.cardsreader.md) > [subscribe](./devices.cardsreader.subscribe.md) ## CardsReader.subscribe() method Starts listening for card reader events. Signature: ```typescript subscribe(reader?: string): Promise; ``` ## Parameters | Parameter | Type | Description | | --- | --- | --- | | reader | string | an optional name of a card reader to listen. If no name is provided, the API will start listening all card readers. | Returns: `Promise`