How to increase the data rate

[Ryon_pan]

Hi, I want to send 9000bytes one sencond.But when I send these bytes it will return error code is 19.

I had increased the ATT MTU to 274 with the function of nrf_ble_gatt_att_mtu_periph_set(&m_gatt, 247);     I use SDK15.0

anyboby konw why? 

[Bjørn Kvaale]

The max ATT MTU size you can use is 247. See this documentation: "ATT_MTU size: The default Maximum Transmission Unit (MTU) is 23 bytes. When increasing this value, longer ATT payloads can be achieved, increasing ATT throughput."

You tried to increase the att mtu size even higher, which is not possible.