Step 1: After pair and connect with the 1st phone, please turn off the phone's Bluetooth.
Step 2: Turn off 10BS (Press and hold the MFB button for 4s)
Step 3: Enter 10BS into pairing mode - Press and hold the MFB button for 7s until LED flashes Blue & Red alternately.
Step 4: Active Bluetooth on your 2nd phone, tap to connect with 10BS.
Step 5: Active Bluetooth on your 1st phone, tap to connect with 10BS. Now 10BS has been connected with 2 devices simultaneously.