The amplifier unit, model EVD-C, provides SPDT alarm contacts for connection into the alarm protective circuit. The EVD-C is housed in a metal cabinet protected by a cover tamper and a housing vibration detector. The housing detector is provided with a housing sensitivity control. A low voltage plug-in transformer and a regulated battery charging circuit maintain the standby battery at a fully charged state.
An auxiliary output is provided to power the APC-B (accumulator option) when required. The battery provides in excess of 80 hours standby operation even if the maximum 6VDC auxiliary output is utilized.
The EVD-C provides an AC on indicator (green LED), a test button, and an alarm indicator (red LED) for subscriber testing of the EVD-S System. Terminals are also provided for connection of a remote test unit, Model PTU-B, and/or connection of dry contacts from any Underwriters Laboratories Listed central station test unit.
From 2 to 15 pickup units may be connected to the EVD-C in a series supervised pickup loop. The supervision of the pickup loop is maintained by a factory adjusted DC differential circuit, which makes