# Subscribing to a Binary subject
The page provides an overview of how to subscribe to a subject of type [Binary](../datasource/datasource-binary.md).
## Requirements
To use the [Binary data type](../datasource/datasource-binary.md), your Caplin components and libraries must be at least as recent as the versions listed in the table below:
**Product versions supporting the Binary data type**
| Product | Minimum Version |
| --- | --- |
| C DataSource API | 8.0.12 |
| Java DataSource API | 8.0.11 |
| .NET DataSource API | 8.0.12 |
| Liberator | 8.0.15 |
| Transformer | 8.0.8 |
| StreamLink Java | 8.0.7 |
| StreamLink JS | 8.0.7 |
| StreamLink .NET | 8.0.7 |
## Overview
To subscribe to a Binary subject using [StreamLink JS](https://docs.caplin.com/developer/api/streamlinkjs/latest/), follow the steps below:
1. Implement the `onBinaryUpdate` method in your implementation of [SubscriptionListener](https://docs.caplin.com/developer/api/streamlinkjs/latest/classes/SubscriptionListener.html). The method receives an event object of type [BinaryEvent](https://docs.caplin.com/developer/api/streamlinkjs/latest/classes/BinaryEvent.html). The `BinaryEvent.getBinary()` method returns the binary object.
```js
var subscriptionListener = {
...
onBinaryUpdate: function (subscription, event) {
var binaryData = event.getBinary();
console.log(binaryData.toString());
}
...
};
```
2. Subscribe to the Binary subject and connect
```js
streamLink.subscribe("/EXAMPLES/BINARY/AAPL", subscriptionListener);
streamLink.connect();
```
## Example
The StreamLink Live Examples packaged with Liberator include an example of subscribing to binary data.
To view the live example, follow the steps below:
1. Deploy Liberator to a Deployment Framework
2. Activate Liberator’s **LiberatorWebsite** and **LiberatorDemoDataSource** built-in blades:
```
./dfw activate LiberatorWebsite LiberatorDemoDataSource
```
3. Start deployed components:
```
./dfw start
```
4. Open a web browser, and navigate to http://localhost:18080/docs/sljs/interactive/#tutorial/binary-subscription
The source code for the live example is reproduced below:
**Example: subscribing to a Binary subject**
```html
Binary:
No Binary Data Received
Log:
```
---
**See also**:
* [Binary data type](../datasource/datasource-binary.md)