ble_app_uart advertising device name length

[Julian]

Hi, 

I am playing around with the BLE relay & ble_app_uart example, and I noticed that on the ble_app_uart example, I can set the device name string to quite a considerable length of 22 bytes (for a total advertising length of 49 bytes).

Whereas on the BLE relay example(using vendor specific NUS UUID, HRS & RSCS removed) the device name string is limited to 4 bytes (for a total advertising length of 31 bytes) .

Question is, I would like to know how does the ble_app_uart does this as I would like to replicate that on the BLE_relay example as well.

I've tried comparing the services_init and advertising_init functions but could not find any significant differences.

Help appreciated.

Thanks.

[Susheel Nuguru]

Hi Julian,

I do not think that you are able to send more than 31 bytes of advertising data on the primary channel. I think ble_app_uart is using scan_response data to send addition data.

In practice you can send 31 bytes of advertising data and 31 bytes of scan_response data (if the peer is doing active scanning byt sending scan request commands)

[Julian]

Hi Susheel,

I thought of using the scan rsp data too but I can't find anywhere in the ble_app_uart example of how to actually do this. Can you point out some examples of the scan response data utilization? 

Thanks.

Edit: I decided to run through the example again and of course, the NUS UUID is embedded in the scan response data inside the advertising_init() function. 

Thanks for your help!