I did this experiment. At the smartphone, I deleted all about the pc. At the PC, I deleted all about the smartphone Using plasma widget, I pair the smartphone. In the plasma widget, I check the smartphone is in the state "trust". At the smartphone, I check the list of the available protocols. There is only HSP. The smartphone is connected with HSP. At the PC, I disconnect the smartphone, then reconnect the smartphone. At the smartphone, I check the list of the available protocols. There are HSP and A2DP. The smartphone is connected for HSP and A2DP. At the smartphone, I disconnect then reconnect the PC. There is only HSP. The smartphone is connected with HSP ! Conclusion : there is a problem when at the smartphone I connect the PC I get only HSP