ATTACHMENT_21_-_IAGP_Instruction_Manual_Part_II.pdf

SECTION I INTRODUCTION

1.1 Purpose and Function

1.1.1 The Interface/Alarm Generator (IAG) was developed by

Chronometrics, Inc. , Silver Spring, MD under Contract DTCG23-84- C-5003l for the U.S . Coast Guard. This IAG is a redesigned version of one originally specified by U.S. Coast Guard Fleet Drawing Series FL-6502-7.

1.1.2 Basically the IAG provides interconnections and alarm

generating circuits for a ship's public address system. The function of the IAG can be described by the three purposes it serves.

1.1.3 The IAG permits lMC microphone stations to be

selectively switched through a Bogen preamplifier and 250 watt power amplifier, to one or several speakers located in various zones of a Coast Guard Cutter. The IAG provides for relay switching of up to four lMC microphone stations .

1.1.4 An alarm generator circuit card provides alarm

voltages for General Quarters, Chemical and Collision alarms.

These voltage waveforms are routed to the 250 watt power amplifier and thence to the zone speakers. An alarm is not, however, routed to the bullhorn used for ship-to-ship communication. Activation of the ship's alarm switches commands the selection of an alarm in order of priority. A Collision alarm has the highest priority, and Chemical alarm has the second priority, over General Quarters alarm.

1.1.5 The purpose of the Interface is to enable front panel

toggle switches to select alarm generator circuit cards (main or standby); microphone preamplifiers and/or power amplifiers (main or standby); and speakers (GP-1 through -6) connected to the Interface.

1.1.6 A relay circuit card is provided for switching the

high currents required by the 250 watt power amplifiers. Another card is provided for switching of the audio and alarms to and from the selected preamplifiers and power amplifiers.

1.1.7 The IAG system can be configured with either two or

four 250 watt power amplifiers. Typically, these options are provided as follows:

1.1.7.1 provides drive in amplifier

Medium switching all six serves as

Endurance Cutter (WMEC Class): The IAG logic for 250 watt power amplifier speaker zones. (A second Interface selectable power a standby unit).

RFP 70Z07918RPT200200 Attachment 21

1.1.7.2 Ice Breaker Cutter (WAGB Class): The !AG provides

switching logic for two each 250 watt power amplifier paralleled to the Interface. One power amplifier drives speakers in zones 1, 2 and 3. The second power amplifier drives speakers in zones 4, 5 and 6. (Two additional 250 watt power amplifiers paralleled to the interface serve as standby units).

1.2 Capabilities

1.2.1 Interface

1.2.1.1 Switch Selection: Alarm Generator No. 1 or No. 2

(Main/Standby)

1.2.1.2 Preamplifier/Power Amplifier

Class: A/A; A/B; B/A; B/B. WAGB Class:

B+B'/A+A'; B+B'/B+B'

Combinations: WMEC A+A'/A+A'; A+A'/B+B';

1.2.1.3 Microphone to Speaker combinations from Speaker Group Station Modules: BRDG; QDK(P); ODK(S); AUX

1.2.1.4 Speaker Group Select: GP-1 through GP-6

1. 2 . 2 Alarm Generator

1.2.2.1 General: Gong sound, repeated 100 times per minute

upon ship switch closure.

1.2.2.2 Chemical : 1 KHz blast for duration of ship ' s

chemical alarm switch closure.

1.2.2.3 Collision: Interrupted version

Three sharp blasts followed by 60 msec. On, 420 msec. idle time before repeat. Total blast is 720 msec.

NOTE

of chemical signal.

60 msec. Off, then time duration of one

The Bullhorn, GP-1 Speaker Group, is used for ship to-ship communication. The Alarms are not routed to the Bullhorn.

1.3 Performance Characteristics (WAGB Class System)

1.3.1 Switches up to 250 watts audio power to one, several, or all of six speaker sets .

1.3.2 Interfaces two preamplifiers (A and B) to Microphone

Speaker Group Station Modules, and four power amplifiers (A+A' and B+B') to up to six speakers.

1.3.3 Collision Alarm, when activated by ship's alarm

contacts, has priority over other alarms. Chemical Alarm has priority over General Alarm.

1.4 Reference Data

1.4 . 1 Electrical and Physical Characteristics of the equipment are listed in Table 1-1.

Equipment and Cabling Required But Not Supplied are listed in Table 1-2.

Special Tools and Test Equipment Required are listed in Table 1-3.

TABLE 1-1

Electrical and Physical Characteristics

Alarm Generator Interface Panel

Dimensions 19 in. (48 cm) x 7 in. (18 cm) x 17.75 in. (45.1 cm)

Volume 2361 cubic inches {38,967 cubic cm)

Weight 18 lbs. (7.7 kg)

Power Requirements 115 VAC (+ 5%) 60 Hz shipboard power fused for- 1 Amp

Environmental Requi rements and Limitations

Altitude, operating

Altitude, non-operating

Ambient Temperature, operating

Ambient Temperature, non-operating

Up to 5,000 ft. (1.5 km) above sea level

Up to 50,000 ft. (15 km) above sea level

32 degrees Fahrenheit (zero degrees Celsius) to 122 degrees Fahrenheit (50 degrees Celsius)

-20 degrees Fahrenheit (-35 degrees Celsius) to 140 degrees Fahrenheit (60 degrees Celsius) at 95% max.

relative humidity.

TABLE 1-2

Equipment and Cabling Required But Not Supplied .

Equipment

TB-2

TB-2

TB- 5

TB-5

TB-6

TB-6

TB-5

TB-5

TB- 6

TB-6

TB-3

TB-4

- Bogen Div. of Lear Seigler, Inc., Paramus, NJ 07652:

(or equivalent)

2 ea. Model CDM Mixer-Preamplifiers 2 ea. Model TCB-250 Power Amplifiers 4 ea. Model TCB-250 Power Amplifiers

(Both Classes) (WMEC Class) (WAGB Class)

- Shipboard Speakers (as required) Loudspeaker, PM, 50 or 70 VDC, 7.5 Volt-Amp

(Type LS -387 B/SIC)

As Required: One watt (LS-306) Seven watt (LS - 387)

- lMC Microphone Station and Speaker Group Select

BRIDGE; QDK(P); QDK(S); AUX

Interconnect Cables

From To Class

9,10 PREAMPLIFIER A OUTPUT BOTH

11,12 PREAMPLIFIER B OUTPUT BOTH

3,4 POWER AMPLIFIER A INPUT WMEC -

7 ,8 POWER AMPLIFIER A OUTPUT WMEC -

3,4 POWER AMPLIFIER B INPUT WMEC -

7,8 POWER AMPLIFIER B OUTPUT WMEC -

3,4 POWER AMPLIFIER A' INPUT WAGB

1,2 POWER AMPLIFIER A' OUTPUT WAGB

3,4 POWER AMPLIFIER B' INPUT WAGB

1,2 POWER AMPLIFIER B' OUTPUT WAGB

4,5 ,6 SHIP'S ALARM CONTACTS

1- 12 SPEAKERS 1 TO 6

lMC Speaker Group Select Modules BRDG;

QDK(P); QDK(S); AUX

TB-1

TB-2

TB-2

TB-2

Interface Panel TB-1 Interface Panel TB-2 MIC Input, Preamplifier A MIC Input, Preamplifier B

TABLE 1-3

Special Tools and Test Equipment Required

- Attenuators, 40 dB, Chronometrics, Inc.

Dwg. No. 011-02-19-7000 or equivalent

- Audio Signal Generator, Hewlett-Packard Model 200, or equivalent

- Dummy Load circuit, Chronometrics, Inc. Dwg. No.

011-02-14-1000, or equivalent

- Oscilloscope, storage, Tektronix Model 564 B, or equivalent

- True RMS Digital Multimeter, Simpson Model 467, or equivalent

- Variable Power Transformer, Stace Type, 1510, or equivalent

- Watch, with second hand

1.5 Warranty

1.5.1 All equipment manufactured by Chronometrics, Inc. is

warranted against defect in material and workmanship for a period of one year from date of installation, FOB plant, when equipment is properly installed and subjected to normal use and service for which it was designed. This warranty specifically exempts and does not cover fuses, solid state customer-replaced components, and other expendable items or materials having a normal replacement cycle or schedule.

1.5.2 Chronometrics, Inc. will repair or replace, at its

option, any defective part, item, or material which may fail within the one-year warranty period if:

1.5.2.1 The defect is not the results of any damages incurred while in transit from the factory.

1.5.2.2 The equipment is free from any alterations of any

kind as to user design, and free of parts not supplied or approved by Chronometrics, Inc.

1.5.2.3 The claim of defect under this warranty is made

within thirty (30) days after discovery thereof, and normal and satisfactory safeguards have been properly executed to prevent any possible further damage to the equipment due to the defective item or material.

1.5.3 Any warranty, whether expressed or implied, that is

not specifically set forth herein (or in contract DTCG23-84-C- 50031) will not be considered applicable to any equipment sold or otherwise furnished by Chronometrics, Inc. Under no circumstance does Chronometrics, Inc. recognize or assume any liability for any loss, damage or expense arising either directly or indirectly from the use or handling of products manufactured by Chronometrics, Inc., or any inability to use them separately or in combination with other equipment or materials, or from any other case except as specified by contract.

1.6 Safety Precautions

WARNING

Dangerous voltages exist inside the IAG. Be careful when workng near the Input Power Terminal (TB-7) and and the +5 and +24 volt power supplies.

Additional safety precautions are given throughout this manual.

Ship's Alarm

Contacts

Shipboard Power 115 VAC, 60 Hz

<X>

Preamp A nput

T B

Preamp B

Input

Speak~ __ l_-_6 ____ -., Input

Power Amp.

A

Output (and A') T B

Input Power Amp.

Interf>ice/ Alarm

Generator

B (and B')

Output

TB 2 TB 1

lMC Speaker T Group Select

'"------------ B Modules : BRD l QDK(P); QDK(S)

AUX

FIGURE 2 .0

Interface Alarm Generator Interconnecting Diagram

SECTION II PREPARATION FOR USE AND INSTALLATION

2.1 Unpacking and Inspecting

2.1.1 Examine the shipping container for damage before the

IAG is unpacked. If the container is damaged, try to have the carrier's agent present when the equipment is unpacked. If not, retain the shipping container and packing material for the carrier's inspection if damage to the equipment is evident after it has been unpacked.

2.1.2 See that the equipment is complete as listed on the

packing slip. Contact Chronometrics, Inc. with details of any shortage.

2.1.3 The IAG was thoroughly inspected and factory adjusted

for optimum performance prior to shipment. It is, therefore, ready for use upon receipt. After uncrating and checking contents against the packing slip, visually inspect all exterior surfaces for dents and scratches. Inspect the chassis and panel for apparent damage. Check the wiring harness for loose connections and the printed wiring boards which may have been loosened from their receptacles.

2.2 Installation

2.2.1 Turn front panel POWER switch to OFF position. Refer

to Overall System Wiring Diagram (C .G. Fleet Drawings FL-6502-7, Rev. C), and Table 1-2 for a listing of equipment and interconnections. Refer to the Mixer-Preamplifier and Power Amplifier equipment manuals and schematics for wiring, cabling fabrication, and any other interconnecting requirements.

2.2.2 Reference Figure 2 . 0 for a recommended WMEC System

Configuration. The WAGB configuration is the same, with the addition of one main and one standby 250 watt power amplifier to cover three additional zones.

2.2.3 Mount the 19 x 7 inch panel in a standard 19 inch

equipment rack. Provide a minimum of 3 inches behind the near chassis for the routing of the interconnecting cables.

2.2.4 Allow sufficient ventilation for the power supplies

located at the right and left front of the chassis. Allow sufficient cooling and ventilation for the power amplifiers and preamplifiers.

2.3 Initial Adjustments

2.3.1 The following adjustments are required upon

connection of preamplifiers (A and B) and Power Amplifiers (A and B) or (A+A' and B+B') to the IAG .

NOTE

These ad justments will also determine if the system is operational. If malfunctions are noted, refer to Troubleshooting in Section 5 . 2 .

2.3.2 These i n i t i a l adj us t ments are based upon the List of Equipment and Cabling Required But Not Supplied given in Table 1-2 above. Refer ence t he manufact urer's equ i pment manuals for additional information . Your system ma y differ , but the basic adjustments required are t he same.

2.3.3 Power Amplifiers A a nd B (and A' , B ' i f used ) must be initially set at a nominal value .

2.3.3.1 dummy load ohmeter.

Reference the Dummy Load circuit and set the 25 resistor to read 20 + 0.5 ohms as observed on ohm the

2.3.3 . 2 Connect the recommended test equipment, and dummy load resistor in accordance with Dummy Load circuit , to IAG TB-4 terminals 3 and 4 . (Connect the speaker to TB- 4 terminals 3 and 4 if desired).

CAUTION

The dummy load resistor becomes HOT during testing.

Locate the resistor where there is air circulation, where it will not present a fire hazard, and where you wi ll not accidentally touch it.

2.3 . 3.3 Se t SPEAKER GROUP MASTER SWITCH swi tches GP-1, and GP-3 through GP- 6 to OFF pos itions . Set ALARM GENERATOR SELECT switch to position 1. Set PRE-AMP and PWR-AMP select switches to position A. Set SPEAKER GROUP MASTER SWITCH GP- 2 to ON position.

2.3.3.4 Connect the RMS voltmeter across the dummy load . It

is suggested that an oscilloscope be used for the following ad j ustments to observe signs of distortion or clipping .

2.3.3.5 Close the ship's alarm contact for CHEMICAL Alarm

(or place a short across TB-3 terminals 1 and 5) while making the following adjustments.

2.3.3.6 Adjust AUDIO INPUT (screwdriver adjust) on rear panel of Power Amplifier A until 20 + 0.1 volt RMS is observed on the RMS vol tmeter connected across the dummy load. Observe the waveform on the oscilloscope for signs of distortion and clipping.

2 .3 .3. 6 .1 When t he WAGB Class Power Amplifie r Al is used, connect the Dummy Load circuit (and speaker) t o IAG TB-5 terminals 1 and 2. Repeat procedures 2.3.3.2 through 2.3.3.6 for Power Amplif ier A'.

2.3.3.7 Set PRE-AMP and PWR-AMP select switches to position B.

2.3.3.8 Repeat procedures 2.3.3.5 and 2.3.3.6 and adjust

Power Amplifier B.

2.3.3.8.1 When WAGB Class Power Amplifier Bl is used connect

the Dummy Load circuit (and speaker) to IAG TB-6 terminals 1 and

2. Repeat procedures 2 . 3.3 . 5 and 2.3.3.6 and adjust Power Amplifier B'.

2.3 . 3.9 Remove the Dummy Load circuit a nd test equipment from !AG TB-4 terminals 3 and 4. Reconnect the speaker leads t o terminals 3 and 4.

2.3.4 Preamplifiers A and B must be adjusted next for an

optimum drive level for Power Amplifiers A and B. The following are the recommended procedures.

2.3.4.1 On Preamps A and B make these initial front panel

control adjustments. Refer to the equipment manuals for additional information.

2.3.4.1.1 vu +10/ +4 dBm switch to +10 dBm position

2 . 3 . 4 .1. 2 MASTER Volume Control to 4

2 . 3 . 4 .1. 3 BASS to midrange

2 . 3.4.1.4 TREBLE to 0

2 . 3 . 4.1 . 5 MIC 1 to position 2

2.3.4.1.6 MIC 2 through MIC 6 to position zero

2.3.4.1.7 Verify that LINE/MIC (recessed switches) 1 to 4 in

rear are set to MIC positions.

NOTE

These adjustments will determine if the microphone system is operational. If malfunctions are noted, refer to Troubleshooting in Section 5.3 below.

2.3.4.2 For these adjustments establish a voice, or telephone communications link, between the lMC Speaker Group Select Station modules (BRDGE, QDK(P), QDK(S) and AUX ) , the location of Preamplifiers A and B, and the OFFICERS speaker.

NOTE

After optimum setting of the Preamplifier MIC Controls, mark the control indications for future reference.

2.3.4.3 At the IAG, set MIC SPKR SEL SW to BRDG ON position.

Verify that the other three positions are OFF . Set SPEAKER GROUP MASTER SW GP-2 (OFFICERS) to ON.

N

Power Amp A

Input Preamp A Output

Preamp B e-J :~ ! Power Amp B

;~~fl,~~

SEL SW ! ~ ~ ALARM

To TB-1 T

To I

GENERATOR

SELECT

1 o r 2

----<>-1'' Powe r Amp A f ""' Kl I to K6 Output

I Power Amp 8

--o--P I +24V

AlK7

A2 U4

AlK2

To Alarm Contact s

~~>---+--llilr---4 Alarm

~...._-o-~-+-41--+~-tl-~~~.crine from

~ A3

_,,/1 Alarm Generator Cards I and 2

Figure 3.0 Rela y Switchi ng Logic Diagram

2.3.4.4 At the lMC Speaker Group Select Module - BRDG, have

someone set OFFICERS Switch to ON position (and verify that the other switches are in OFF position). Have that person talk into the microphone· and while someone is listening at the OFFICERS speaker, adjust Preamp A MIC 1 (BRIDGE) control for a good listening level as heard at the OFFICERS speaker . Communicate between these three locations via the voice or telephone communications link.

2.3 . 4.5 position .

At the IAG, set MIC SPKR SEL SW to QDK(P) Verify that the other three positions are OFF.

ON

2.3 . 4.6 Repeat procedure 2.3.4.4 at the lMC Speaker Group Select Module - QDK(P), and adjust MIC~ control of Preamp A.

2.3.4.7 At the IAG set MIC SPKR SEL SW to QDK(S) ON position.

Verify that the other three positions are OFF.

2.3.4.8 Repeat procedure 2 . 3.4.4 at the lMC Speaker Group

Select Module - QDK(S), and adjust MIC l control of Preamp A.

2.3.4.9 At the IAG set MIC SPKR SEL SW to AUX ON position.

Verify t hat the other three posit ions are OFF.

2.3.4 .10 Repeat procedure 2.3.4.4 at the lMC Speaker Group sel ect Module - AUX, and MIC i control of Preamp A.

2 .3.4.11 position B.

On the I AG set PRE-AMP and PWR- AMP select switches t o

2.3.4 . 12 Repeat procedures 2.3.4 . 3 through 2.3 . 4.10 but adjust MIC 1 through MI C 4 controls of Preamp B.

SECTION III THEORY OF OPERATION

3.1 Introduction

3.1.1 The WMEC Class cutter uses two (one main, one

standby) 250 watt power amplifiers (A and B). The WAGB Class Cutter uses four (two main, two standby) 250 watt power amplifiers (A, A' and B, B' ). These amplifiers A, A' and B, B' have parallel inputs at IAG Terminal Boards TB-5 (3,4) and TB-6 (3,4 ) .

3.1.2 The WAGB Class system has Power Amplifiers~ and A'

driving IAG TB-5 terminals 7, 8, and 1, 2. Power Amplifiers B and B' drive IAG TB-6 terminals 7, 8 and 1, 2.

3.1 . 3 The Theory of Operation of the IAG is the same for both systems. PRE-AMP/PWR-AMP switch positions on the IAG panel still reference A/A, A/B, B/A and B/B .

L---i.------·----

Waveform Figure 3.1 l,....--------~ U3A, Pin 1 10 mSec./Div . Horiz.

1 Volt / Div. Vert.

D. C. Coupled Source Trigger

Collision Rate Waveform t--~-+-~~~~-+-~-+~~+-~-+~~+--~-+-~--t~~~U3B, Pin 13 Collision Alarm S~itch Closed 0 . 5 mSec. / Div . Horiz.

1--~-+-~~~~-+-~-"'~~+-~-+~~+--~-+-~~1--~~ 1 Volt/Div . Ve r t .

D. C. Coupled t.:==::::1-.~--J=::=:::l-.~-..l====l-~-l:====l-~~==~f--~~Source Trigger

Waveform Figure 3.2 Collision Tone Waveform

UlA, Pin 1 L--~..J-~......J.~~"'-~--l-~~1--~-+-~-+~~-t--~-+~--tGeneral Alarm Switch Closed

0.5 mSec./Div. Horiz.

l:===:t::==::::::t:==~~~+-~-J:====l~==+:='.:1~~---t~--+2 Volts/Div. Vert.

Waveform Figure 3.3 Gong Tone Waveform i..- -

L---

L..--- L--

L---... -

Waveform Figure 3.4 Gong Rate Waveform

D. C. Coupled Source Trigger

UlB, Pin 13 Storage Oscilloscope General Alarm Switch Closed l Sec./Div. Horiz.

1 Volt/Div. Vert.

D. C. Coupled Single Sweep Triggering: Normal

+ Slope

/1

I/ / i\

Junction Rl7, Cl2 Storage Oscilloscope General Alarm Switch Closed 2 Sec./Div. Horiz.

0.2 Volt/Div. Vert.

D. C. Coupled Single Sweep Triggering: Normal

+ Slope

Waveform Figure 3.5 Gong Carry Waveform

3.2 Switching Logic

3.2.1 Reference C.G. Dwg. FL-6502-7, Sh. 15, Overall System'Wiring Diagram, and Figure 3.0, Logic Diagram, and Schematic Diagrams, C.G. Dwgs.

B, Sheets 16, 17, and 18.

REV. B, for the Relay Switching

FL-6502-7, REV.

3.2.2 PRE-AMP and PWR-AMP select switches direct relays A2U3

and/or A2U4 to connect Preamp A/Preamp B outputs to inputs of Power Amp A/Power Amp B. These switches also energize/deenergize power relay A1K7 to connect, in parallel, the output of Power Amp A or B to the inputs of power relays A1Kl to A1K7.

3.2.3 A logic low from the GENERAL/CHEMICAL/COLLISION alarm

contacts, or from the Alarm Line to Alarm Generator Card A3 will cause Dual AND Drivers AlU2 and AlU3 to switch low and energize power relays AlK3 to AlK6, and switching A2U2 to provide an alarm for GP-2 while disabling GP-1.

3.2.4 The Alarm Generator Output will be connected to Power

Amplifier A/B input via A2U3 and A2U4 while the preamp A/B output will be switched to an open condition.

3.2.5 Quad NAND Driver A2U2 logically directs the BULLHORN

circuit to TB-4 terminals 1 and 2.

3.2.6 In the ALARM mode the Quad NAND will place a low on one AlUl Dual AND Driver and a high on the other Dual AND Driver.

Power relay A1K1 (to the BULLHORN) will release, and power relay A1K2, to TB-4 terminals 3 and 4, will energize. Therefore, upon the activation of the Alarm Generator Circuit (A3) power relays A1K2 to AlK6 will connect the Power Amplifier output to TB-4 terminals 3, 4 to 11, 12.

3.3 Alarm Generator

3.3.1 Reference Schematic Diagram C.G. Dwg. FL-6502 - 7, Sh.

18, REV. B for Alarm Generator Card A3. Waveforms appearing at the IC Discharge terminals are illustrated in Waveform Figures

3.1 through 3 . 4.

3.3.2 Integrated Circuits (IC) Ul and U3 are dual (556)

timers configured as astable multivibrators. The astable mode is obtained by connecting the trigger to the threshold inputs. The timing resistor is split into two separate (one adjustable) resistors with their junction point connected to the timer's discharge terminal.

3.3.3 Collision Alarm pulse rate, COLL RATE; Collision tone

COLL TONE; Gong tone pulse rate, GONG TONE; and Gong

GONG RATE are adjusted by R8, Rl, R19 and R18 pulse rate, pulse rate, respectively.

3.3.4 The combination of R14, R17, C12 and D2 form a low

pass filter with a long and short RC time constant. This circuit is used to produce a GONG tone with a fast rise time and slow decay time. The RC time constant is adjustable by R14, GONG CARRY, and the waveform is illustrated in Waveform Figure 3.5.

3.3.5 IC U7 (556 timer) is configured as a monostable

multivibrator. The width of the output pulse is determined by R25, R24 (ALARM DURATION), and C20. Once triggered by a low on GENERAL ALARM at DS, D7, the output of U7 will remain in a high state until the set time has elapsed.

3.3.6 Activation of the alarm circuits is accomplished by

a ground (logic low) at the junction of diodes D3, D6; D5, D7;

and D4, DB.

3.3.7 As long as CHEMICAL alarm is logic low, astable

multivibrator U3A is not in reset mode and is running at an approximate 30 Hz rate. The characteristic CHEMICAL alarm tone is produced from the U3A waveform.

3.3.8 U2 is configured as a divide-by-six counter. QD

output, pin 8, provides a logic low for counts O to 5, and a logic high for counts 6 to 11. The QA output, pin 12, produces alternate high and low pulses. Through Inverter USA, pin 3 Output, only three pulses are high during the count interval O to 11, (or during the 2.5 Hz interval).

3.3.9 U2 runs as long as there is a logic low on Reset, pin

10 through Inverters U4B and U4D.

3.3.10 When COLLISION alarm is activated, output of Inverter

U4A is high, and astable multivibrator U3A is reset and turned off.

3.3.11 When both COLLISION and CHEMICAL alarms are

activated, the output of Inverter U4D is high, and Collision Tone multivibrator is reset and turned off. The logic high, from U4D, is inverted by USD, which in turn resets and turns off monostable multivibrator U7.

3.3.12 When monostable multivibrator U7 is triggered by a

low GENERAL alarm logic, it starts timing, and its output becomes high. Resets are removed from GONG Tone multivibrator UlA and from GONG Rate multivibrator. They are placed in the energized mode.

3.3.13 The output of U7 is inverted to a low logic state

through Inverter USC which, through Dl, places a low on the ALARM

LINE.

3.3.14 U6 and US are electronic attenuators used to provide

compression and expansion of the tone waveforms, and therefore, provide pure tone waveforms.

1 4

Figure 4.0 Front Panel Controls and Indicators

Item Name

l. POWER switch

2 . ALARM GENERATOR

SELECT switch to to

PRE-AMP A or B Select Switch

PWR-AMP A or B Select Switch

MIC SPKR SEL

SW switches

SPEAKER GROUP

MASTER SWITCH

switches

DS-1

PS-1

1 AMP

DS-2

PS-2

1 AMP

Function Turns A.C. Power ON a nd OFF

Selects Alarm Generator Circuit Card l or 2

Selects Preamplifiers A or B

Selects Power Amplifi e rs A or B

Turns ON/OFF 1 HC MIC SPKR Group Station Modules

BRDG; QDK (P); QDK (S): AUX

Select speakers GP-1 through GP-6 connected to Interface Panel Terminal Board No. 4

Power Supply 1 Blown Fuse Indicator Lamp

+ 24 Volt Power Supply Fuse

Power Supply 2 Blown Fuse Indicator Lamp

+ 5 Volt Power Supply Fuse

Table 4.0 Front Panel Controls and Indicators