I have been successfully using chan_dongle for past week, works great thanks for all the work.

I am using spa-2000. I have a single E1550, when I receive a call waiting tone I flash, I can switch to the new incoming call, but I cannot switch back to the original call.

First call is put on hold. When I press flash to switch back to the first caller, I hear on hold music.

Both callers are connected but I can toggle between second caller and hold music by pressing flash.

I can hang-up but the first caller stays on hold indefinitely.

I am very new to Asterisk/FreePBX world. Please help me fix this issue, I will greatly appreciate.