- Is CS-818 in bypass mode when the it is turned off?
Nope. CS-818 uses magnetic relays and it stays the same as the last tuning status before you turn it off.
- What are online/bypass modes?
There are basically 2 status in CS-818 - online and bypass. 'Online' means CS-818 is taking part in the system while 'bypass' indicates the opposite - Your radio is directly connected to your antenna when it is in 'bypass' mode.