Loop amplifiers shall be self-tuning. Manual tuning by any means is not acceptable. Detectors shall reach full sensitivity within 10 seconds of the application of power. All integrated circuits shall be socket mounted. Sockets shall have machined beryllium copper contacts with gold plating. Surface mounted technology can be substituted for socket mounted. Amplifiers shall sequentially scan each channel to eliminate crosstalk between loop systems. It shall be possible to operate the amplifier with all channels connected to the same loop. Loop amplifiers shall incorporate a single LSI signal processing integrated circuit. Any custom or programmed integrated circuits used shall be readily available from the manufacturer. Detector units shall select sensitivity levels, frequency of operation, pulse or presence modes, and reset on a per channel basis. All settings shall be operator settable from the front panel. Loop amplifiers shall operate with a loop lead in with a minimum of 305 meters. Loop amplifiers shall tune to a loop system of 20 to 2000 microhenries (+/- 3%); provide 9 or more levels of sensitivity and 8 or more frequency settings. Each channel shall continue to operate with a single point short to ground on the loop or loop lead-in. Each channel shall automatically recover from intermittent opens or multiple shorts to ground. An intermittent open shall be stored in an open loop memory. The channel indicator light shall display an open loop condition, short circuit condition, or 25% step change in inductance. Amplifiers shall have a backlit liquid crystal display and be able to display inductance, sensitivity level and frequency. Presence mode shall provide a call hold time of at least 4 minutes with a typical call hold time of 2 hours. In pulse mode the minimum pulse shall be 125 milliseconds. Amplifiers shall have an audible detect signal that is automatically disabled a minimum of 15 minutes after activation or the loss of power. Amplifiers shall have a minimum range of 1 to 63 seconds in 1 second increments for call delay and a minimum range of 0 to 15.75 seconds with maximum increments of .25 seconds for call extension. Each channel shall have the capability of being turned off. Each loop detector shall be packaged in a separate box. BRAND & MODEL NO. BID: EDI ORACLE 2E or approved equal. The vendor or manufacturer shall provide a written warranty (with bid packet) that the product furnished will perform in accordance with the requirements of this specification for a minimum period of 12 months from the date of acceptance by the purchasing agency. A written warranty against defects in materials and/or workmanship shall also be furnished. Items that fail within the warranty period will be returned to the vendor for a full replacement.
