I want to get more into Bluetooth LE. So, I have seen the GATT server example, which works fine. But I want to start to communicate with my device. So I could use a simple service such as the alert notification service, but I need something more customizable. The IPSP service would be nice, but since NimBLE does not support it yet, we can skip that. So, I could use the UART transport layer, but this is not included in RIOT. So the last option is the RAM transport layer. I think it makes sense to go with it. My problem here: How does it work, are they any simple examples? I looked already into the code, there is no ACL for it. How did you add ACL to your device?