The CM-CU21 is a high-quality portable commentator unit. Its robust construction and flexibility make it suitable for a wide variety of environments. It offers two fully-equipped commentator positions and a third guest position that can also be used as a line-level input. Each position has an individual output, with two additional outputs providing a mix of all active commentary channels. A limit indicator on the main panel shows when the adjustable limiter on the mix outputs is active, and a bright 21-segment LED VU meter, which can be disabled, displays the main output level. Two intercom output channels, with a built-in limiter, are available for each of the two main commentators and they can be linked to provide simultaneous operation. A wide input gain range and switchable phantom power on each commentator position allow for support of a variety of microphone types, including low-output ribbons, headsets and high-output phantom-powered microphones. There are 4 transformer-balanced audio return inputs which, along with the commentator inputs, are routed to the headphone monitoring controls. With these headphone controls, any monitoring input can be adjusted and sent to the left ear, right ear or both. A GPIO port provides open-collector output indication of any active On-Air or intercom channel and four remote inputs provide external call/alert to each of the intercom controls. The unit has a built-in alignment tone generator for easy channel identification and cable checks. When activated, the test signal is routed to the required output simply by pressing the corresponding on air or intercom button. An On-Air lock switch prevents the On-Air buttons from being accidentally deactivated and a T/B Gang switch links the operation of intercoms A & B. A flexible range of options allows customisation of the commentator unit to better meet the operational and personal requirements of the user. This includes options for momentary or latching operation of intercom buttons, permanent enabling or disabling of any commentator input, default routing of headphone signal and illumination levels of main panel indicators. The CM-CU21 commentator unit can be powered by a universal mains input between 85-264V AC at 47-63Hz, or by a 12-24V DC input. Features of the CM-CU21 Commentator Unit - 2 commentator positions plus one guest position, each with individual outputs; plus 2 mix outputs. - Intercom outputs selectable by both main commentators, with built-in limiter. - 4 return audio circuits routed to headphones along with all commentator inputs. Any source can be individually controlled in level and sent to left ear, right ear or both. - A wide input gain range and switchable phantom power on each commentator position allow for support of a variety of microphone types, including low-output ribbons, headsets and high-output phantom-powered microphones. - Individually switchable 48V phantom power on all microphone inputs. - User-preset adjustable limiter on main mix outputs with limit activity indication. - Built-in alignment tone for initial cable checks. - 21 segment LED VU meter showing main output level. - Transformer-balanced inputs and outputs. - Built-in 'Sharpie' formica designation strips. - Robust mechanical design with protection for potentiometer buttons. - Universal AC mains power supply, or 12-24 volt DC power.