What is the exact maximum data_length I can set to send in BLE?

[Ziyao Zhou]

Hi,

I notice that every time I can only send 244 bytes per time in nus service, if I set higher I will not receive the data in RX. 

But I also see that the thoughput sample we can set data_length to 251.

Which one should be the exact one? Thank you for your help!

[Simonr]

Hi

Please check out the Maximum throughput blog post here, that explains all there is to know about MTU and data length in BLE. The data length and total packet lengths are slightly different, since there is some overhead that won't be part of the payload of BLE packets.

Best regards,

Simon