The Scarlett 18i20 audio interface caters for a total of 18 inputs and 20 outputs, and provides the means to connect microphones, musical instruments, line level audio signals and digital audio signals in both ADAT and S/PDIF formats to a computer running compatible versions of macOS or Windows via one of the computer’s USB ports. In the Third Generation, the optical ADAT ports also support “Dual ADAT” operation (S/MUX II), which provide 8 channels of audio at 88.2/96 kHz as well as at 44.1/48 kHz. The signals at the physical inputs can be routed to your audio recording software / digital audio workstation (referred to throughout this user guide as the “DAW”) at up to 24-bit, 192 kHz resolution; similarly, the DAW’s monitor or recorded output signals can be configured to appear at the unit’s physical outputs. 4 The outputs can be connected to amplifiers and speakers, powered monitors, headphones, an audio mixer or any other analogue or digital audio equipment that you wish to use. Although all inputs and outputs on the Scarlett 18i20 are routed directly to and from your DAW for recording and playback, you can configure the routing within your DAW in order to meet your precise needs. The accompanying software application, Focusrite Control, provides further routing and monitoring options, as well as the ability to control global hardware settings such as sample rate and synchronisation. Two completely new features have been added to the Third Generation 18i20: talkback and secondary monitor speaker switching. The Talkback function uses the built-in mic to let you speak to the musicians through their headphones, though the talkback signal may alternatively be routed to any other combination of outputs. The ALT function lets you connect a second pair of monitor loudspeakers to Line Outputs 3 and 4 and switch between the pairs to reference your mix on a different set of speakers. Both functions can be activated from the front panel but they can also be configured and selected on-screen from Focusrite Control. All inputs on the Scarlett 18i20 are routed directly to your DAW software for recording, but Focusrite Control also allows you to route these signals internally within the device to the outputs so that you can monitor the audio signals with ultra-low latency - before they arrive at your DAW, should you need to do so. The Scarlett 18i20 also has connectors for sending and receiving MIDI data, and for transmitting word clock to ensure synchronisation with other items of digital audio equipment.