Hi, for the Hardware flow control switch on the SD1000, here is the manual's explanation:
"Parani-SD1000 plugged into its host system transmits data from host to the other side Bluetooth device.
This data is saved temporarily in the internal buffer of Parani-SD1000 and sent repeatedly until the
transmission is completed packet by packet. When the radio transmission condition is not good enough
to send data promptly, it can cause a transmission delay. If the host sends more data when the buffer is
full, buffer overflow will make Parani-SD1000 malfunction consequently. In order to prevent this buffer
overflow, Parani-SD1000 works as follows.
When using hardware flow control, Parani-SD1000 disables RTS so that it stops receiving any further
data from the host when the buffer becomes full. RTS will be re-enabled again to begin receiving data
from the host when the buffer has created more room for more data.
When hardware flow control is not being used, the Parani-SD1000 clears the buffer to secure room for
the next data when the buffer becomes full. This can mean a loss of data may occur. As the transmission
data becomes large, the possibility of data loss becomes greater.
For large data transmissions, the use of hardware flow control is highly recommended."
We will look into a fix for the connection process.
I attached the manual for reference. Thank you!