The YO-100 Monitor- scope consists of a monitor of "On the air" signal and an oscilloscope. A two tone signal generator is built-in for SSB adjustment, and the cabinet design of the YO-100 and YO-101 matches that of the entire family of equipment in the Yaesu FT-101 series, FT-277/FT-201 transceivers, FR-101, FL-101 Twins.