This portable unit adds more versatility to the Altair E-200 serie intercom system as it allows to recognize a call in noisy and complex enviroments. The unit remotly feeds itself as in the beltpack mobile units and carries an additional connector to chain more extensions to the line. As in the rest of the system, a high sound buzzer with switch on/off selector from the front panel as the switch off remote function from the central unit or buzz-kill function for its application in silent environments.