True if Toss Mode was successfully entered.

If the stream responds to a CR with a CID prompt indicating connection to a CM-5 in Manage Mode, then a 't' and CR are sent to enter Toss Mode. The CM-5 must first be manually placed in Managed mode by pressing the Mode button until the Manage LED is lit. If the CM-5 is responding, but not in Manage Mode an exception will be generated. Calling this method should generally be OK, even if not connected to a CM-5.