The 6820EVS panel and accessories provide features to meet the requirements for Mass Notification Systems as described in UL 2572. The 6820EVS is an intelligent addressable Fire Alarm Control Panel combined with an Emergency Voice System (EVS) and are direct replacements for the 5820XL-EVS FACP. When the EVS features are enabled, they are integrated with the fire alarm and voice evacuation functions of the control panel. The emergency voice system operations include an onboard supervised microphone. All-call and non-active call buttons can quickly select all active or non-active output groups. The system also allows for emergency messages over fire. The 6820EVS FACP has one built-in signaling line circuit (SLC), which can support 159 SK detectors and 159 SK modules, or 127 SD protocol devices. Additional SLC loops can be added for a maximum of 1110 (SK) or 635 (SD) points per panel. The built-in digital alarm communicator/transmitter (DACT) is dual technology, IP and POTS. The POTS transmits system status (alarms,troubles, AC loss, etc.) to aCentral Station via the public switched telephone network. The IP communicator's internet monitoring capability sends alarm signals over the Internet saving the monthly cost of two dedicated business telephone lines. Although not required, the secondary telephone line may be retained providing backup communication overthe public switched telephone line. Optional cellular reporting is available. The 6820EVS has six onboard Flexput circuits that can be configured as notification outputs or auxiliary power. The 6820EVS also has a form-C trouble relay, and two programmable form-C relays, along with powerful features such as drift compensation, pretrouble maintenance alert, a built-in sensor test to comply with NFPA 72 calibration testing requirements, and a calibration trouble alert. A common communications and annunciation link allows up to 17 panels to be connected via copper or fiber optic cable. A designated panel is configured as the communicator for all panels in the link for convenient single-point communications.