The Keysight (formerly Agilent) 86105A incorporates two measurement channels -- one optical, the second electrical. Each channel has two selectable bandwidth settings. In the lower bandwidth mode of 12.4 GHz, oscilloscope noise performance is excellent, while the 20 GHz mode allows greater fidelity for high-speed signals. The optical channel also has a switchable filter to produce a calibrated SDH/SONET reference receiver. The integrated optical channel reduces mismatch loss variation by eliminating signal distorting cables and connectors associated with the use of external receivers in order to accurately characterize optical waveforms. The optical channel is calibrated at 1310 nm and 1550 nm to provide accurate display of the received optical waveform in optical power units and measurement of the signal's average power. Switchable filters for compliance testing at 155, 622, 2488 or 9953 Mb/s are available. The electrical measurement channel may be used to perform measurements on tributary electrical signals, to evaluate receiver performance in transceiver testing, for measurements with Keysight (formerly Agilent)'s wide range of external optical receivers, or for general purpose measurements.