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2.3.4 Radio Communications Failure Condition (RFC)

Radio communications failure condition (RFC) is declared when Telguard is unable to transmit

over the cellular network even with acceptable signal strength. Two conditions can cause an RFC

to occur, Link Request failure (RFC1) or Link Termination failure (RFC2).

2.3.4.1 RFC1 (Link Request Failure)

When a LFC or CFC has been declared and there is an alarm signal to communicate, the

Telguard attempts to transmit its message via radio. When the C/C goes off-hook, the

Telguard transmits a Link Request to the TCC and waits for a Link Request ACK. If the

Telguard does not receive an ACK for the transmission before the C/C hangs up, it will

retransmit the Link Request again when the C/C goes off-hook for a redial attempt. If the

Telguard does not receive an ACK after three attempts, then an RFC will be declared

which trips the STC relay, causes the STC LED to flash five times and switches the

Telguard to Telco. Restoral of RFC occurs when the communication cycle is completed.

2.3.4.2 RFC2 (Link Termination Failure)

After the Telguard receives a Link Request ACK from the TCC, the Telguard

communicates with the C/C to acquire the alarm message and transmits the message via

radio. If the Telguard does not receive a link termination ACK (where the TCC

acknowledges receiving the transmission) within 150 seconds, it will retry sending the

entire transmission. Upon failing two attempts, the Telguard switches to Telco and allows

the C/C to communicate directly with the Central Station. An RFC is declared causing the

STC relay to trip and the STC LED to flash five times. Restoral of RFC occurs when the

communication cycle is completed.

2.4 C

OMPLETE

OWER

UPERVISION

Telguard monitors its backup battery as well as its AC power source and reports low or missing power

conditions from either. Telguard’s integrated control and power module, protected by a 3 amp 3AG fuse,

incorporates battery charger circuitry that is jumper selectable for high or low battery capacities. The high

battery capacity selection is used for 12V 7Ah, or 12V 21Ah batteries.

2.4.1 Low/Missing Battery Condition (LBC)

The Telguard checks the backup battery voltage on initial power-up and every minute thereafter.

Additionally, a battery voltage test is performed by the Telguard every 24-hours while operating on

AC power in order to measure the loaded battery voltage. Battery charging voltage is lowered to

10.0 volts and the Telguard is forced to operate entirely from the battery supply. If the battery

voltage is less than 11.6 volts, a LBC is declared whereby the STC LED blinks twice (½ sec ON, ½

sec OFF, ½ sec ON, ½ OFF every 5 seconds) and the STC relay trips. When the battery voltage

increases to 12.1 volts, the STC LED and STC relay restore.

2.4.2 AC Failure Condition (ACFC)

AC failure condition (ACFC) occurs when AC power is lost or less than 102 VAC for 6 continuous

hours. The AC Power LED goes out immediately, the STC LED blinks once and the STC trip output

is activated after 6 hours. When AC power returns too normal (

≥

106 VAC for 60 seconds), the AC

Power LED turns on immediately and the STC trip output restores after 60 seconds.

2.4.3 Watchdog Monitor/Reset (WR)

A watchdog monitor/reset (WR) circuit continuously monitors the Telguard’s internal operating

microprocessor functions.

2.4.4 Catastrophic Failure (CF)

Catastrophic Failure (CF) is any condition that causes the Telguard to stop functioning at all levels.

Most commonly because of AC power failure followed by a complete discharge of the backup

battery. The STC trip output is activated and visible indication is loss of all LED activity. Total

loss of power to Telguard does not prevent transmission of alarm messages from the host C/C

“through” the Telguard and out over an operative phone line in the normal fashion.