Hi,

I send an 11 byte message to a device and it responds with 75 bytes of data. On USB Serial ports the response comes in 10-15 msec. On Bluetooth SPP connections it takes 60-70 msec. That is all normal.

My problem is on a Mac with a Bluetooth SPP the first response is normal but if I then send another message straight away the response comes back a little slower. Each subsequent message comes back slower and slower until I am waiting 250 msec for a response. If I then slow down my message sending to once per second after a few message the response time comes back down to 60-70 msec.

This effect does not happen on Windows.

I have no concerns about the device I am talking to as I have used it with Bluetooth SPP under Windows using a Visual Studio app without problems.

Are there any buffer or similar settings that I can adjust that might effect this? Either via Qt or via Mac settings?

I think it is not related but I have noticed that CTS is not set for Mac Bluetooth SPP connections whereas in all other cases it is.

Thanks

Brian