DEVELOPMENT OF A 

CALL ALERT SYSTEM 

FOR PAGING MINE PERSONNEL 

John Trornbly, Program Director 

Stuart Lipoff, Paul O'Brien 

prepared for 

1 UNITED STATES 

DEPARTMENT OF THE INTERIOR 

BUREAU OF MINES 

ARTHUR D. LITTLE, INC. 

CAMBRIDGE, MASSACHUSETTS 

FINAL REPORT 

On Contract No. HO 262026 

) Arthur D Little,Inc 

I 
USBM H0262026 

DEVELOPMENT OF A CALL ALERT SYSTEM 

FOR PAGING MINE PERSONNEL 

John Trombly -- Program Director 

Stuart Lipoff, Paul O'Brien 

ARTHUR D. LITTLE, INC. 

Cambridge, Massachusetts 02140 

C-79492 

USBM CONTRACT FINAL REPORT (H0262026) 

UNITED STATES 

DEPARTMENT OF TIEE INTERIOR 

BUREAU OF MINES 
REPORT DOCUMENTATION PAGE 

1. Report No. 2. 3. Rocipieat'r Accarion No. 

4. Title and Subtitle 

Development of a Call Alert System for Paging Mine 

Personnel 

7. Author(s) 

John E. Trombly, Program Director 

Stuart Lipoff, Paul O'Brien 

9. Performing Organization Name and Address 

Arthur D. Little, Inc. 

15 Acorn Park 

Cambridge, Massachusetts 02140 

12. Sponsoring Organization Name and Address 

Office of the Assistant Director - Mining 

Bureau of Mines, Department of the Interior 

Washington, D. C. 20241 

r 

15. Supplementary Notes 

J 

5. Report Date 

r I 

6. 

8. Performing Orgmiution Report No. 

79492 

A 

10. Projtct/Tark/Work Unit No. 

J 

11. Contract or Grant No. 

H0262026 

13. Type of Repon 

Final Report 

L J 

14. 

- 16. Abstract 

System objectives and design criteria for an in-mine ULF radio paging system are discussed. 

Coding formats, frequency and bandwidth selection criteria leading to the system design 

are discussed. The prototype call alert transmitter and pocket page receiver is functioaally described. The report includes circuit descriptions, schematics, parts lists, 

printed circuit fabrication and assembly drawings. The report concludes with an estimate 

of the manufacturing cost for each assembly. 

17. Originator's Key Words 

Mine Communications, Personnel Pagers, 

Radio Paging, Pager Phones, Pager Telephones, 

Paging. 

18. Availability Statement 

19. U.S. Security Classif. of the Report 

Unclassified 

J J 

20. U.S. Security Clasrif. of Thir Page 

Unclassified 

21. No. of Paga 22. Price 
FOREWORD 

This report was prepared by Arthur D. Little, Inc., Cambridge, Massachusetts under USBM Contract No. H0262026. The contract was initiated under 

the Coal Mine Health and Safety Program. It was administered under the 

technical direction of the Pittsburgh Mining and Safety Research Center 

with Mr. Harry Dobroski acting as the technical project officer. Mr. 

George Honold was the contract administrator for the Bureau of Mines. 

This report is a summary of the work recently completed as part of this 

contract during the period June 1976 to Jtine 1977. 

No inventions or patents were developed ard no applications for inventions or patents are pending. 

Arthur D Little Inc. 
TABLE OF CONTENTS 

LIST OF TABLES 

LIST OF FIGURES 

I. INTRODUCTION AND SWY 

A. OBJECTIVE 

B . SYSTEM DESCRIPTION 

C. FINDINGS AND CONCLUSIONS 

11. THE CALL ALERT SYSTEM 

A. BACKGROUND 

1. Page Queuing 

B. TECHNICAL DESCRIPTION 

1. Call Alert Transmitter 

a. Introduction 

b. Nomenclature 

c. Power Supply 

d. Visual Pager Interface 

e. Transmitter Logic 

f. Modulator 

g. Transmitter Power Output Stage 

h. Local Operation 

2. Call Alert Receiver 

a. Introduction 

b . Nomenclature 

c. Power Supply 

Page 

v 

vi 

1 

1 

3 

6 

iii 

Arthur D Little IK 
TABLE OF CONTENTS (Continued) 

d. Receiver Front End 

e. Demodulator 

f. Decoder 

111. MANUFACTURING COST ESTIMATE 

A. SUMMARY 

B. CALL ALERT RECEIVER 

C. CALL ALERT TRANSMITTER 

APPENDIX 1 - COST ESTIMATES 

APPENDIX I1 - PARTS LISTS 

APPENDIX 111 - VISUAL PAGER SCHEMATIC DIAGRAM 

Page 

38 

39 

40 

42 

42 

42 

43 

Arthur D Little Inc 
LIST OF TABLES 

TABLE 1 CALL ALERT SYSTEM CODES 

TABLE 2 UART PIN ASSIGNMENTS 

Page 

20 

Arthur D Little Inc 
LIST OF FIGURES - 

FIGURE 1 

FIGURE 2 

FIGURE 3 

FIGURE 4 

FIGURE 5 

FIGURE 6 

FIGURE 7 

FIGURE 8 

FIGURE 9 

FIGURE 10 

FIGURE 11 

FIGURE 12 

FIGURE 13 

FIGURE 14 

FIGURE 15 

FIGURE 16 

THE CALL ALERT SYSTEM, BLOCIK DIAGRAM 

POCKET PAGE RECEIVER 

CALL ALERT TRANSMITTER 

TRANSMITTER SWITCH PANEL 

DIFFERENTIAL PHASE SHIFT KEYING 

OCCUPIED BANDWIDTH, 3Hz 

OCCUPIED BANDWIDTH, 30 Hz 

OCCUPIED BANDWIDTH, 300 Hz 

UNMODULATED REFERENCE 

BLOCK DIAGRAM - CALL ALERT TRANSMITTER 

BLOCK DIAGRAM - CALL ALERT RECEIVER 

TRANSMITTER SCHEMATIC 

RECEIVER SCHEMATIC 

RECEIVER ASSEMBLY DRAWING 

RECEIVER COMPONENT ASSEMBLY DRAWING, BOAZiI) 1 

RECEIVER FABRICATION DRAWING, BOARD 1 

vi 

Page 

2 

Arthur D Little Inc. 
LIST OF FIGURES (Continued) 

FIGURE 17~/B RECEIVER ARTWORK DRAWING, BOARD 1 

FIGURE 18 RECEIVER COMPONENT AS SEMB1,Y DRAWING, BOARD 2 

FIGURE 19 RECEIVER FABRICATION DRAWING, BOARD 2 

FIGURE 20~/B RECEIVER ARTWORK DRAWING, BOARD 2 

FIGURE 21 VISUAL PAGER SCHEMATIC 

Page 

32, 33 

vii 

Arthur D Little Inc. 
I. INTRODUCTION AND SUMMARY 

A. OBJECTIVE 

For a number of years, coal mines small and large have made extensive 

use of party line pager telephones to communicate into and between 

working areas as well as to supervisory sites above and below ground. 

These phones page the callee by means of a self-contained loudspeaker; 

normal communications are then carried on by a conventional telephone 

hand set. The acquisition range depends on how audible the speaker is, 

as well as on the number of phones in a given area, and the chances of 

a callee being in their vicinity. 

Clearly, there are operational drawbacks to the system. To remedy these, 

the use of visual pager units has been proposed, and engineering models 

of such units are currently under develop~ment. These, in their simplest 

form, are display panels which, when sele(ctive1y activated, show symbols 

to designate paged individuals who have not been reached via the voice 

paging sys tem. 

These display panels enlarge the paging area and can be installed where 

phones are not needed. Unless these display panels are read by all concerned, they too, like the pager phone wi:Ll sometimes fail to notify an 

individual that he is being paged. 

The ultimate system is a wireless scheme which can selectively page any 

one of a number of miniature pocket receivers carried by key mine personnel; thereby providing each of these ir~dividuals with a personal 

alerting signal that he should call in. Such wireless schemes can cover 

a large working area, and are almost impossible to ignore. 

From a system engineering point of view, all three paging techniques: 

phone, visual, and wireless perform basically the same function; and 

they benefit greatly by being made modules of a complete paging system 

which uses any or all three modes of communication. Figure 1 illustrates 

the system concept. This shows the existing pager phone hardware, the 

visual pager hardware developed by ADL for the Bureau, and the additional 

equipment necessary to add the wireless page capability. 

Arthur D Little, Inc. 
DISPATCHER'S 

CONTROL CONSOLE 

VISUAL PAGER 

VISUAL PAGER SYSTEM 

--- ----- ---------------- ---- ---------I-------- ------- --- 

CALL ALERT SYSTEM 

I WIRELESS 

I 

I 

I TRANSMITTER 

I 

I UNDER DEVELOPMENT AT ADL 

L --------,-,,,,,-,,,,,,,,,,,,,,-

BLOCK DIAGRAM 

CALL ALERT SYSTEM 

WITH PROTOTYPE VISUAL PAGER 

Figure 1 
The objective as outlined in this figure is to provide an add-on wireless pager system that is fully compatible with the existing voice pager 

phone equipment and with the visual paging system previously developed. 

B. SYSTEM DESCRIPTION 

The call alert system, as delivered to the Bureau of Mines, is comprised 

of three prototype pocket page receivers, a compact page transmitter 

and an interconnecting cable to interconnect a visual display with the 

transmitter. The system can be expanded, without modification, to page 

a total of 15 receivers and then the capacity of the system is only 

limited by the visual pager's dispatcher's console. The pocket receivers, 

shown in Figure 2, are designed to accommodate 32 distinct codes without modification. If the design capacity is perceived to be a limiting 

factor, the receivers can be expanded to a field of 128 codes with only 

a very minor modification. 

The receiver, as depicted in Figure 2, is completely self-contained. 

The enclosure houses a ferrite loop antenna, aural and visual alarms, 

two printed circuit cards and a rechargeable nickel cadmium battery 

designed to provide approximately 40 hours of continuous service between charges. Two contacts are provided at the bottom of the receiver 

for charging from a 12-volt source. 

When the receiver is switched on, the aural alarm sounds to indicate to 

the wearer that the batteries are charged and the receiver is operational. If a page is received corresponding to the code stored in 

the receiver, the aural alarm sounds for about 2 seconds and the light 

emitting diode illuminates steadily. The LED can be reset by depressing 

the slide switch. 

The receiver's address code is programmed by inserting wire bridges in 

a header located on the upper printed circuit card. This dip header 

is visible in the upper left-hand portion of the disassembled receiver 

in Figure 2. 

The call alert transmitter is shown in Figure 3. The enclosure houses 

a wire wrapped card assembly, rechargeable battery and a switch panel 

Arthur Little Inc. 


for installation and system test. The transmitter can be operated on a 

stand-alone basis, completely independent of the visual pager system for 

test purposes. In normal operation, however, the transmitter is controlled 

by a dispatcher's console, using an existing pager phone line as a communications link. The transmitter derives decoded signals by plugging into a 

standard visual display or a battery/receiver box such as shown in Figure 1. 

The transmitter's battery is designed to accommodate up to 7,000 pages 

between charge cycles. As the battery is depleted, the transmitter 

loses power without disabling the visual display that the transmitter 

may be interfaced with. 

The transmitter may be controlled manually from a switch panel, pictured 

in Figure 4, located just inside the hinged front cover. The switch 

panel permits code selection, antenna tuning and remote/local control. 

C. FINDINGS AND CONCLUSIONS 

The call alert system has been successfully demonstrated at the ADL 

building complex and grounds as well as at the Bureau of Mines test 

mine in Bruceton. The primary performance criteria for a paging system 

are, of course, paging range and falsing rate, particularly when the 

receiver is operating in an area of intense electromagnetic interference. 

The paging range meets with our original system goals of 500 to 1000 

feet as a function of surrounding strata and electromagnetic noise. 

Typical paging range at the Bruceton mine was estimated to be 700 feet, 

according to the Technical Pro j ec t Monitor. 

One false page was detected during controlled tests at Bruceton, but 

only while the transmitter endlessly repeated a specific code. Since 

the test was conducted during a 20 minute period, during which 2,200 

pages were transmitted; one false page is equivalent to a falsing rate 

of one every 73 days if 30 pages per day is assumed to be a typical 

radio paging rate. 

The call alert receiver is most suscepti'ble to falsing at the fringe 

of a signalling area and only if the receiver passes through a field 

below the receiver's capture range during the course of the page. Both 

Arthur D Little lnc 

conditions must occur since not only muslt the receiver synchronize with 

the incoming data stream, but the code must match the five bit code 

stored by the receiver. In addition, pa.rity and framing conditions 

must be met. 

In addition to paging performance, system goals emphasized design of 

a compact lightweight and rugged paging receiver. Figure 2 clearly 

indicates the small size of the receiver, made possible by extensive 

use of LSI technology, without resorting to hybrid circuits or other 

manufacturing techniques not commonly employed by the mining communications industry. 

Arthur D Little Iw. 
11. THE CALL ALERT SYSTEM 

A. BACKGROUND 

Since the choice of an operating frequenlcy based upon field tests was 

beyond the scope of this project, the 3 kHz band currently in use by 

Collins Radio was selected to minimize contingencies. It is believed 

that this band offers the advantage of optimum range traded against the 

disadvantages of high ambient noise and large physical antenna size. 

It is further hypothesized that the use of this low frequency will permit a simple, low power and low cost receiver design. 

Conventional radio paging receiver modulation schemes have employed 

baseband modulation of audio tones onto the carrier frequency. Size 

and cost economies in these state-of-the-art pagers have employed 

mechanical tuning fork filters in the audio frequency range of 300 Hz - 

3 kHz. These conventional baseband audio tone techniques were judged 

to be unsuitable for our Call Alert System. At a carrier frequency of 

3 kHz, baseband tone modulation of even 300 Hz would require such a 

large relative occupied bandwidth about the 3 kHz carrier, that the 

system range would be expected to suffer. Furthermore, the use of 

mechanical filters which are sensitive tro shock is not compatible with 

the mine environment. The use of audio tone frequencies below 300 Hz 

with active filter techniques is possible, but the large physical size 

and high cost requirements of the required capacitors make this approach 

unattractive. Furthermore, the signalliing time per page for these low 

frequency tones my be expected to be substantial. 

Digital coding schemes on the other hand offer flexibility in system 

performance; permitting sensitivity, code set size, signalling time, 

and falsing performance to be easily traded off against one another. In 

addition, digital decoders permit straightforward homogeneous integrated 

circuit custom designs which in turn enhance size and current drain 

performance. 

Phase Shift Keying (PSK) is a special case of FSK that is ideally suited 

for this application. By choosing the differential scheme shown in 

Arthur I3 Little Inc 
Figure 5, the modulator is easily implemented and the demodulation process is straightforward, provided phased-lock loop techniques are employed 

to recover the data. The coherent demodulation provided by the phaselocked loop insures maximum system range as predicted by signal detection 

theory. Furthermore, PSK provides an approximate 6 dB reduction in required received power for the same CW system performance.* 

The occupied bandwidth required by the signal of Figure 5 was measured 

using a synchronous modulator connected to an HP3580A spectrum analyzer. 

The modulator input signal consisted of a 50% duty cycle square wave of 

modulation frequency 3, 30, and 300 Hz. The spectrum analyzer photographs are attached as Figures 6, 7, and 8. Figure 9 is a photograph 

of an unmodulated carrier for reference. Note the following features 

of the spectrum: The carrier frequency is nulled out, the first set of 

sidebands is +/- the modulation rate and 4 dB down from the carrier, 

the other sidebands are spaced multiples (of the modulation rate and fall 

off rapidly with increasing spacing from the carrier. To a good approximation, the occupied bandwidth is equal to four times the modulation 

rate. In general, the carrier will not disappear for a modulation bit 

stream with a duty cycle different from 50%; but in this case, the 

occupied bandwidth will also be less so the above approximation is a 

good upper bound. 

The 30 Hz modulation rate has an occupied bandwidth of 120 Hz and thus 

would permit the carrier and its modulation products to be placed between the 180 Hz >phase power line harmorric noise prevalent in the 

mines. The 30 Hz data rate permits an eight bit serial word to be transmitted in about 260 ms, not an unreasonable delay in comparison to a 

dispatcher's keying interval when operating the console. 

The system protection against false alarms will, to a large extent, determine 

the acceptance of the system by the users. Commonly used rates for cow 

*Bennett and Davey, Data Transmission, McGraw-Hill, New York City, 1965. 

Arthur Il Little Inc 

Figure 7 

qlation Rate 30 Hz, Horizontal Scale 50 Hz/Div 

Arthur D Little, lnc 
Figure 9 

Unmodulated Reference 

Arthur D Little, lnc 
mercial radio common carrier paging should also apply to the mining 

application. Industry standard limits a.re 0.1% falses per total pages 

transmitted. The system design should i.nsure that falsing rates for 

random noise falsing are not significant. compared to single bit falsing 

on a valid page intended for another pager. 

1. Page Queuing 

While posting a sequence of pages in the Visual Pager system, a fleetfingered dispatcher could post pages at the maximum system rate of 200 ms 

per page. Consequently, a queuing delay occurs while the transmitter 

serially outputs a page. A visual pager processes the data in real time 

and therefore has no need to store the pages. The burden for storing 

pages as they are generated by the dispatcher is placed on the Call Alert 

transmitter. 

When viewed from a systems perspective, four solutions to page queing appear 

feasible. In the first approach the length of the pager code could be 

shortened to a total of six bits to dispose of the delay. The field of 

addresses would be reduced to about four unique codes. Although as few 

as four addresses may be sufficient to evaluate the Call Alert System, no 

flexibility is provided for future expansion. 

The second approach considered would retain the aforementioned data rate 

but would only store the current page for transmission. The transmitter's 

input port would go into a busy mode while a page is transmitted and 

additional pages posted by a dispatcher would be ignored, until the 

current transmission is completed. Sincre considerable time could expire 

between pages, this approach offers a reasonable tradeoff. 

The third approach considered would store all of the pages as they were 

posted by the dispatcher. The capacity of the memory would permit the 

entire roster of 15 possible pages to be stored in the sequence of 

their posting. The transmitter would serially step through the memory 

stack until it arrived at a page for transmission. The page would be 

transmitted and a portion of the memory reservzd to count the number 

of times that page was outpulsed would be incremented. If the page 

Arthur D Little, Inc 
was incremented n times, where n in this case is equal to perhaps 5, it 

would be erased from the memory stack. Following a page cycle, the 

transmitter would step to the next page in sequence in the stack. If 

the dispatcher repeated the posting of a page still current in the stack, 

the counter would be reset to n = 0, rather than re-entering the page. 

The contents of the memory would not overflow with the repeated entry 

of the same page. When the transmitter completes outpulsing of all 

pages currently in the stack, power would be switched off until a new 

post command is received from the dispatcher. 

The last approach considered is a truncated form of the processing scheme 

described above. Rather than storing the entire field of 15 possible 

pages, only two pages are stored. One is currently being transmitted 

while the second page, if it is posted, i,s stored. Each page is repeatedly transmitted, as described earlier. If a third page is posted 

sequentially, then the first page received by the Call Alert transmitter 

is bumped. It should be noted here that this arrangement permits a 

reasonable probability of transmitting at least three sequential pages, 

even at the hands of a fleet-fingered dispatcher. As the dispatcher 

keys the third page, 600 ms have elapsed, so the first page has already 

been transmitted. The disadvantage, of course, is clear. The first 

page is bumped and therefore is only trainsmitted once. 

We consider the programmable processor approach to be beyond the scope 

of the present Call Alert contract. We do feel, however, that the 

second approach offers a reasonable alternative since it simplifies the 

hardware interface, lowering production costs without incumbering page 

processing from the dispatcher's viewpoint. With the above discussion 

as background, block diagrams for the transmitter and receiver were 

developed and are illustrated in Figure 10 and 11, respectively. A 

detailed functional description of the Call Alert System is included 

as the introduction to the Technical Description below. 

Arthur D Little, Inc 
VISUAL PAGER 

4- BlTS 

DATA STROBE 

u 

POWER UP 

EXTERNAL POWER 

CODE SOURCE ,B, , XIXI KI 4 %l 

COCAL/REMOTE CODE SELECT SWITCH 

? 

MCf40T60 h 

MC14519 B TRE OPSK \ 

3 QUAQ DATA M T 

LATCH 0 

4- 

> 

0 A 

mD.5 

4 3KiZ 

T T 

POST 0 

R 

c=f+.t 

4- 8\Ts 

A 

1.0 MHz 

COUNT =O 3086.42 Hz 

I CLK 

z n MSZC e I 4 

G16Z 5 *2, LOGIC 

- 

LOGIC (lo 1000 lo) 4 

I - SOPPLY 

PROGRAM 

0 -9 POWER 00 

CALL ALERT TRANSM lTTER 

Figure 10 
LOOP 

ANTEMNA 

CODE I I 

BLOCK DIAGRAM 

CALL ALERT RECEIVER 

r\ 

AMPLIFIER ( 1 PREAMPLIFIER, 

3080 Hz PHASE LOCKED 

- BANDFASS LOOP 

FILTER OEMODULATOQ 

. 

THGESHOLD 

OlGlTAL 

ccC0DIhAG 

T 
B. TECHNICAL DESCRIPTION 

1. Call Alert Transmitter 

a. Introduction 

The call alert transmitter is a self-contained unit, housed in a water 

tight steel enclosure with dimensions of approximately 8" wide by 10" 

high by 4" deep, exclusive of the carrying handle and mounting bracket. 

Connector J1 is located to the left of the front panel and interconnects 

with a visual display's accessory connector via a four foot cable provided with the transmitter. Loop antenna connector 52 is located to 

the right of the front panel and contains two spring loaded contacts 

designed to accept strand@d or solid wire to /I10 gauge. 

The transmitter's control switch panel and 4.5 A-H rechargeable gel-cell 

battery can be readily accessed by removal of the two screws that retain 

the hinged front panel. The following switches are located on the panel 

directly above the transmitter's battery: 

Remote/Local Switch 

Code Select Switches (5) 

Antenna Tuning Switches (5) 

A fuse holder is also mounted to the switch panel and will accept a 6 

amp 3AG fuse. 

If the ~em/Loc Switch is placed in the remote position, the transmitter 

will accept and process pages received from a visual pager. When a 

valid code is received, the transmitter will continuously cycle the 

page code for N periods, where N is equal to the setting of the transmit 

cycles switch located on the wire wrap card just above the switch panel. 

This switch may be screwdriver adjusted to transmit from one to nine 

continuously repeated pages. Since a complete page is transmitted in 

530 ms, a sequence of nine repeated pages will require approximately 

4.8 seconds to process. This processing time is important to the dispatcher and should be considered by him as; pages are posted. If the 

dispatcher posts a second page before the transmitter has completed a 

code cycle, the second page will be ignored by the transmitter. 

Arthur ll Little fnc. 
The rechargeable battery housed within the transmitter's enclosure will 

power the unit for approximately 7,000 pages, provided each page code 

is transmitted only once. Typically, a page will be repeated several 

times. As an example, if the transmit cycles switch is set to 5, the 

battery will be depleted following 1,440 past-page sequences. At a 

rate of 30 postings per day, and with the transmit cycles switch set to 

5, the battery should be recharged at intervals of 1-1/2 months. 

The transmitter may be operated independently of the dispatcher's console and the visual display for test purposes. If the Rem/~oc switch 

is placed in the local position, the transmitter will continuously repeat the page code programmed by the Code Select switches located on the 

switch panel. Caution is advised when operating the transmitter in the 

local mode, since a fully charged battery will be depleted in about one 

hour if the antenna is tuned to resonance. 

The correspondence between the page keys of the dispatcher's console, 

transmitter code and receiver code is indicated in Table 1. The transmitter code is not directly equivalent to the receiver code because the 

system employs differential phase shift coding. The transmitter code 

is easily mapped into the receiver code if it is recognized that a 

change from the previous bit transmitted is interpreted as a logic zero 

by the receiver. If the current bit being transmitted is the same as 

the previous bit, regardless if the bit is a one or zero, the receiver 

processes the bit as a logic one. 

The call alert system is designed for a capacity of 32 discrete page 

codes. Since the dispatcher's console is designed for a maximum of 15 

visual pages, slightly less than half the capacity of the call alert 

system is utilized. During remote operation, the fifth data bit is 

always transmitted as a logic one. However, during the "local" mode, 

this bit may be manually programmed by the fifth Code Select Switch. 

Antenna tuning switches are located on tthe switch panel and are used 

to optimize performance of the transmitter at installation. Power 

transfer to the loop is at maximum when the antenna is operated at 

Arthur Il Little Inc 
CALL ALERT SYSTEM CODES 

TABLE 1 

I 

Arthur D Little Inc. 

Visual Display 

Symbol Code 

1248 - --- 

0 0000 

d -F 1000 

5 0100 

3: 1100 

L.5 0010 

r-- 3, 1010 

rzj 0110 

3; 1110 

- 

,A. 0001 

E 1001 

E 0101 

E 1101 

E 1011 

0111 

1111 

Transmitter 

Code 

Parity 

Start I Program Istop 

12345 1 I----- 

I I 

0 looool~ll 

I 

0 ~10001~11 

0 ~01001111 

I 0 ,11001;11 

0 100101111 

I 0 '10101 11 

I 

0 '01101~11 

I 0 '11101,11 1 

0 ,00011111 

0 ~10011;11 

0 '01011111 

I 

0 llloll~ll 

I 

0 ~10111(11 

1 0 'Ollll,ll 

I 

0 ,11111;11 

Receiver 

Code 

Parity , Start I Program l Stop 

1123451 I----- 1 

0 ~11110~11 

I 

0 100110,ll 

0 lloolo~ll 

I I 

0 101010,11 

0 ~llooolll 

0 100000~11 

I I 

0 (10100(11 

0 101100~11 

0 '11101I11 

I 

0 loolol~ll 

0 ~10001,11 

0 ~oloollll 

1 

0 100011(11 

I 

0 ~10111~11 

0 l01111~11 

- 

Receiver 

S . Id, if 

79492- 

0 1 

0 5 

0 2 

0 4 

0 3 
resonance. This may best be observed by monitoring the current waveform during the tuning procedure with a portable battery operated 0scilloscope. Connect the scope ground to terminal 2 of 52 and the probe 

a few inches away from terminal 2, toward the loop. This loop connection 

will function as a current shunt and provides a convenient method of 

observing antenna current. The loop may be tuned by first switching 

the transmitter to the local mode. The current waveform is then observed while the antenna tuning switches are operated until the current 

switching transitions occur at the zero crossing of the current waveform. 

The current switching transitions will be visible as distinct, fast 

rising or falling steps and should be adjusted to coincide with the 

oscilloscope's baseline. The switch bank is designed to accommodate 

an antenna inductance between 75 and 300 ph. 

b. Nomenclature 

The transmitter schematic is shown in Figure 12. All components are 

mounted to a wire wrapped board assembly with the exception of the 

connectors J1, 52 and the battery. Integrated circuits are identified 

by a U followed by a one or two digit number. Wire wrap sockets are 

identified at the top of the socket with their appropriate U designation. 

Most discrete components are mounted on dip headers which are designated 

with a Z followed by a single digit number. The power output transistors 

are mounted to a rear plate but are wired directly to the card assembly. 

The switch panel is wired directly to the card and contains all switches 

indicated on the schematic with the exception of the Transmit Cycles 

switch which is plugged into a dip socket, directly on the card. 

c. Power Supply 

During remote operation, 12 vdc is available continuously at J1-H (VB) 

from a visual display system, Figure21J4-H (VB).t As the display powers 

up in response to d. c. applied to the pager phone line, VS swings positive 

and the 2N3904 switches on. The 2N6109 conducts and applies 11.5 volts 

to VDD, the logic supply. Since the current drain is less than 20 ma, 

the visual pager's battery is not excessively loaded. 

Arthur D Little, lnc. 

The 2.2 uf capacitor (22) is initially discharged and U9B pin 4, the 

master reset line, is high. The Schmidt trigger formed by U4C and U9B 

creates a power up reset pulse about 50 Ins long. U9 pin 4 switches low 

at the end of this period, resetting U5, U7 and U8. 

d. Visual Pager Interface 

The visual pager interface clocks data from Figure 21, J4t appearing on J1 

connector pins BCDl to BCD8 into a storage register (U5) following a valid 

post code. Gates U2B and U4A monitor the ,4 bit bus for a post command 

(0011). If a post word is detected, the D input to D-flop U3A goes high 

and the following strobe pulse on J1-E c:Locks U3A. As the Q output of 

U3A switches state, the set input of U3B goes high, setting the Q output 

of U3B. 

The reset input of U3B also remains high until jam input counter U7 is 

preset. If a second strobe does not fo1:Low the initial post strobe, 

then U3B will reset when U3A is reset. 'fiis occurs when the visual pager 

returns to its power down quiescent mode. However, if a second strobe 

pulse occurs while a post command is stored in U3A, then counter U7 is 

preset and U3B remains set. The Q output remains high and sources sufficient base current to the 2N3904 to keep this transistor conducting. 

Based on the previous discussion, it shoi~ld be clear that the transmitter 

remains powered up even though a visual display has shut down, provided 

the transmitter receives a post command :followed by a second data strobe. 

Post flop U3A enables the input to quad latch U5, permitting the second 

data strobe to clock data present on the bus into U5. 

e. Transmitter Logic 

If S1A is switched to the remote positioin, data present at the output 

terminals of the quad latch (U5) is passed through the 2 channel multiplexer U6 to the Z output bus. The mu1t:iplexer's parallel output is 

terminated at the Universal Asynchronous ~eceiver/~ransmitter (UART) 

transmitter inputs TBR1-4. The UART pin assignments and a brief description of the function of each pin is :included in Table 2. 

Arthur D Little, Inc. 
I 

PIN SYMBOL DESCRIPTION 

1 VCC *5 volts Supply 

2 IM6402-N C No Convectton 

1M6403-Control 4 11 Stage Divider 

~~gh 4 Stage 

LOH 11 Stage 

3 GND Ground 

4 RRD A Htgh level on RECEIVER REGISTER 

DISABLE torces the recelver holding 

reg~ster outputs RBRI-RBRB to a high 

cmpeda~ce state 

5 R BRB The cooteots of the RECEIVER BUFFER 

REGISTER appear on these three-state 

outputs Word formats less than8 characters are rtght justified to RBR1 

6 RBR7 See Pin 5 - RBRB 

7 RBR6 See Pln 5 - RBRB 

RBR5 See Pin 5 - RBR8 

See Pin 5 - RBRB 

See Pln 5 - RBRB 

See Pln 5 - RBR8 

RBR1 See Pln 5 - RBRB 

PIN SYMBOL DESCRIPTION I 

2 1 MR A high lekel on MASTER RESET clears 

PE FE. OE andDR toalow levelandsets 

the trans~~tter output to a high level 

2 2 TBRE A htgh level on TRANSMITTER BUFFER 

REGISTER EMPTY indicates the transm~tter butter reglster has transferred its 

data to rne transmltter reglster and IS 

ready for new data 

2 3 TBRL A low level on TRANSMITTER BUFFER 

REGISTER LOAD transfers data from 

Inputs TBR1-TBR8 rnto the transm~tter 

buffer reglster A low to hlgh transltton on 

TBRL indicates data transfer to the transmltter register If the transmltter register 

is busy. transfer is automat~cally delayed SO that the two characters are transmitted 

end to end 

2 4 TRE A h~gh level on TRANSMITTER 

6 REGISTER EMPTY ~nd~cates completed transrntsston of a character lnclud~ng 

StOPt3ltS 

2 5 TRO Character data, start data and stop blts 

appear serlelly at the TRANSMITTER 

REGISTER OUTPUT 

26 TBRI-TBR8 Character data IS loaded into the 

TRANSMITTER BUFFER REGISTER vla 

Inputs TBR1 -TBR8 For character formats 

less than 8 blts the TBRB. 7. and 6 Inputs are ignored corresponding to the 

programmed word length 

1 

PIN SYMBOL OESCRIPT ION 

13 PE A hlgh level on PARITY ERROR ~nd~cates 

rece~ved partly does not match parity programmed by control bits When part!^ IS 

inhibited this output 15 low 

14 F E A hlgh level on FRAMING ERROR 

Indicates the flrst stop bit was invalid 

15 OE A high level on OVERRUN ERROR 

rndicates the data received flag was not B cleared before the last character was 

\transferred to the recetver buffer reglster 

16 SFD A high level on STATUS FLAGS DISABLE 

forces the outputs PE FE OE. DR TBRE 

to a h~gh tmpedance state 

17 IM6402-RRC The RECEIVER REGISTER CLOCK IS 

IM6403-OSCIN 16% the receiver data rate 

18 DRR A low level on DATA RECEIVED RESE: 

clears the data recelved outputDR. to a 

low level 

19 OR A h~gh level on DATA RECEIVED 

lnd~cates a character has been rece~vea and transferred to the recetver buffer 

regrster 

20 RRI Serlal data on RECEIVER REGISTER 

INPUT IS clocked into the receiver 

register 

L 

PIN SYMBOL DESCRIPTION 

2 7 TBR2 See Pin 26 - TBRl 

2 8 TBR3 See Pln 26 - TBRl 

2 9 TBR4 See Pln 26 - TBRl 

30 TBRS See Pin 26 - TBRl 

3 1 TBR6 See Pin 26 - TBRl 

3 2 TBR7 See Ptn 26 - TBRl 

3 3 TBRB See Pin 26 - TBR 1 

3 4 CRL A high level on CONTROL REGlSTEc 

LOAD loads the control reg~ster 

3 5 PI A high level on PARITY INHIBIT ~nhtb~ts 

parity generation. partty checking aqa 

forces PE output low 

36 SBS A high level onSTOP BIT SELECT se1ec:s 

1 5 stop blts for 5 character torrnat and 2 

stop b~ts for other lengths 

3 7 CLS2 These Inputs program the CHAR ACT E R 

LENGTH SELECTED (CLS1 IOH CLSi 

low 5 bits) (CLS1 high CLS2 loth 6 bits1 

(CLS1 low CLS2 high 7 bits) (CLS1 high 

CLS2 high 8 bits) 

38 CLSl See Pln 37 - CLS2 

39 EPE When PI is low a htgh level on EVEh 

PARITY ENABLE generates anc cheers 

even parity A low level Selects @ad pa..:? 

40 tM6402-TRC The TRANSMITTER REGISTER CLOCK 

IM6403-OSCOUT IS 16X the trensrntt data rate 
When jam input down counter U7 is preset by a data strobe, the "0" output, 

pin 12, switches low, releasing the reset from bflop UlOA. The next 

low to high 3KHZ clock transition sets the Q output of UlOA. The Q 

transition causes the UART to load its transmitter buffer register 

from parallel inputs TBR1-5. Two clock cycles later, the UART begins 

serially transmitting the data, including start, stop and parity bits 

at TRO (pin 25). The eight bit word begins with a logic low (start 

bit) and always ends with a logic high,, two bits long, characteristic 

of the parity and stop bits. 

The transmitter flags the end of a trarlsmission by raising TRE (pin 24) 

high. This output is simply inverted and passed on to the Receiver 

Ready Input (RRI, pin 20). The receiver section of the UART is used 

to generate a one word delay before the next transmission. This delay 

allows receivers to resynchronize if th~ey pass through a dead spot or 

are located in a low signal level area. At the end of a receive cycle, 

data ready output (DR, pin 19) switches high and counter U7 is clocked. 

D-flop UlOA clocks TBRL (pin 23) and the transmit cycle is repeated 

until U7 is finally clocked to zero. The actual number of cycles 

iterated is set by Transmit Cycles switch S2 and may be set from one to 

nine. 

f. Modulator 

A 3kHz clock (3086.42Hz) is generated by counting down from 1 MHz crystal 

oscillator that is also used as the master clock for the UART. Programmable binary counters U11 and U12 divide the 1 MHz clock by 162 and 

U13A divides 617.84 Hz by two to generate the 3086 Hz carrier frequency. 

D-flop U13B and ~nd/~r gate U14 together form the phase shift keyed 

modulator. Two phases of the clock, 180' out of phase are present at 

the Q and ? outputs of U13A. Either the Q and ?j clocks are selected 

by the complex gate and appear at ZA or ZB as a function of the state 

of U13B. This D-f lop clocks the serial data appearing at TRO synchronously 

with the 3kHz clock and therefore controls the phase of the clock gated 

to U14 outputs ZA and ZB. 

Arthur D Little Jnc 
g. Transmitter Power Output S t;age 

Complex gate U14 is disabled until a post command is strobed into D-flop 

U3A and U3B is set. While U14 is disablled, outputs ZA and ZB are low 

and both MPSAO5 driver transistors remain off, conserving power until 

a post command is detected. When U14 i.s enabled, the transmitter is 

keyed as buffer U15 A and D receive the carrier 180" out of phase with 

respect to each other. Parallel connected inverters U15 B-F provide 

adequate current gain to drive the two MPS-A05 switching transistors. 

Transformer T1 provides current gain and level translation to the 

complementary output stage. The transformer also minimizes power consumption during the quiescent power off mode. The collector current 

of the driver transistors is approximately 200ma and the base current 

to the complementary pair is one ampere. The driver and output stages 

are both sourced from the internal 12-volt battery. The collectors 

of the complementary pair drive a switchable set of polystyrene capacitors to se>ries tune the loop antenna as described earlier in the 

introduction. The transmitter's output may be open or short circuited 

without a danger of destroying componerlts in the output stage. The 

output transistors will dissipate about 10 watts each when the output 

is shorted, however, they are mounted to the rear plate to maintain an 

adequate junction temperature safety margin, even if the ambient temperature reaches 60°C. 

h. Local Operation 

The transmitter will repeat the code programmed by the Code Select 

Switches endlessly if ~em/~ocal Switch S1 is placed in the local position. In this mode, S1A disables the cycle counter U7, SIB bypasses 

the power up circuit and SIC permits the fifth data bit to be selected. 

S1A also switches the multiplexer to select data from the code select 

switches. 

Arthur D Little Inc. 
2. Call Alert Receiver 

a. Introduction 

The call alert receiver is a 3 kHz phase shift keying (PSK) receiver 

of the tuned radio frequency (TW) type. The receiver is preprogramed 

with a set of internal switches to respond to its unique 5 bit digital 

code by activating an aural and visual alert. Contained within the 

receiver housing are the rechargeable nickel cadmium batteries and the 

ferrite loop antenna. The unit is designed for belt or pocket mounting 

on the person and no external connections are required for normal use. 

Recharging is accomplished by two external battery terminals located on 

the bottom of the unit and are current limited for intrinsic safety 

against shorting. 

b . Nomenclature 

The receiver schematic diagram is attached as Figure 13. The construction 

of the unit is such that the components a.re spread between two double 

sided printed circuit boards and the case. Components mounted to the 

case are suffixed with digits 1 to 99(e.g. C12), components mounted to 

PC Board ill are suffixed with digits 100 to 199(e.g. R104), components 

mounted to PC Board #2 are suffixed with digits 200 to 299(e.g. 4204). 

Figure 14 depicts the overall assembly of the receiver, including placement of the battery strings. Printed circuit card assembly, fabrication 

and artwork drawings are included in Figures 15 through 17 for board 

number one and Figures 18 through 20 for board number two. 

c. Power Supply 

All circuits in the receiver are operated from 5 vdc. This voltage is 

supplied from BT1 and BT2 as follows: BT1 feeds all circuits except 

the LED visual alert, CR3. CR3 is supplied from BT2. This arrangement 

was chosen to optimize the battery form factor for the case used; 

however, it does offer the advantage that: if the LED is left on and 

BT2 is permitted to run down the receiver will still function with the 

aural alert. 

Arthur D Littlelm. 

T 

rfP : v 3 

L-J l?Y 

t 

- r--- --I T-7 

, 

------ La, \ / 








Switch SWlOO removes all power (both batteries) from the circuit when 

operated but does not break the circuit to the charging contacts. 

Charging is accomplished by means of an external charger which applies 

12 Vdc to the charging contacts. The internal current limiting resistors 

Rl and R2 approximate a 10 mA constant current source charger for the 

batteries. The batteries are rated to withstand this charge rate indefinitely and should be fully recharged after 16 hours. 

d. Receiver Front End 

The receiver front end consists of integrated circuits U101, A & C and 

U102. This section of the receiver acc'epts the input signal from the 

antenna, amplifies and filters it before applying it to the demodulator. 

The antenna assembly is a high Q (about 30) parallel resonant LC circuit. 

The exact resonant frequency is trimmed with the "select at test" capacitor C107. UlOl is biased with Rl21 at 5 PA and under these conditions 

the loop antenna amplifier, UlOlA, runs with an open loop gain of about 

60 dB. The DC quiescent bias point for UlOlA&B, and all of U102 is 

set at about half supply by R120 and Rl21. This bias point is decoupled 

with C115 to ground. The output of UlOlA is coupled by DC blocking 

capacitor C109 to the active bandpass filter circuit of U102. 

The active bandpass filter is a three amplifier state variable filter 

using all three sections of U102. The state variable filter was chosen 

to provide a Q of 30 while minimizing the sensitivity to component 

variations over frequency and tolerance. The center frequency of the 

filter is trimmed by the "select at test" resistor Rl14. The midband 

gain of the active filter is limited by the divider input resistor Rl13 

so that the active filter remains in the linear region even when UlOlA 

is driven into full clip. This approach insures that noise and strong 

signals are controlled in the amount of energy that can be coupled in 

to the demodulator which reduces the probability of falsing on 

extraneous signals. 

The output of the active filter is buffered with a single amplifier 

Arthur D Little, Inc. 
section consisting of U102C with a nominal gain of 20 dB. The output 

of UlOlB is coupled to the demodulator through C102. 

e. Demodulator 

The demodulator circuit consists of U100, UlOlB and U103A. This circuit 

functions by demodulating the carrier PSK phase transitions into 5 Vdc 

controlled pulse width logic level transitions. 

UlOO is a phase locked loop integrated circuit. The voltage controlled 

oscillator (VCO) is nominally tuned to the 3 kHz carrier frequency by 

ClOl and Rl02. This frequency is trimmed at test by selecting Rl03. 

R104 insures the oscillator starting under worst case battery conditions. 

The loop is locked through a proportional plus integral control loop 

filter consisting of Rl00, Rl01, and C100. The filter is selected so 

that the minimum bandwidth consistent ?with the 30 bit per second signalling rate is used. The values were selected empirically to set 

intersymbol interference to zero at thle maximum 30 baud signalling rate. 

The filter damping was set to at least one cycle of ringing to insure 

that both a positive and negative going transition are available regardless of the direction of phase change. The phase detector output 

is buffered internally in UlOO and is supplied to the audio output 

pin 10. 

The phase locked loop output divides at pin 10 into two separate paths 

into the comparator, UlOlB. The first path through R106 is filtered 

by C103 to remove the 3 kHz carrier. 'The other path through R105 to 

C104, provides a longer integration interval compared to R106 and 

C103. So the average DC level of the phase locked loop appears at 

pin 6 of U101. When a phase transition occurs in the phase locked 

loop, the comparator UlOl translates the 50 mV loop output into a 

5 VDC pulse. The comparator output at pin 9 of UlOl is further filtered 

to reduce the 3 kHz carrier by Rlll and CllO and applied to the monstable U103A. 

The negative going transition appearinrg at pin 5 of U103A triggers the 

monostable. The timing interval is se,t by the RC product of R112 and 

Arthur D Little, Inc. 
C111. The timing is adjusted to be eqiual to one nominal bit interval 

at the 30 baud rate. The monostable irs further configured to be retriggerable to any phase changes that occur in the carrier before it 

resets. In the quiescent state the mo~nostable output at pin 7 of 

U103A is high. 

f. Decoder 

The decoder circuit consists of U201, 'U200, U203, U202, and U103B. The 

decoder functions by accepting the serial bit stream from the demodulator 

and provides an alarm signal to the interface circuitry if the received 

code sequence matches the preprogrammed pager code. 

The following conventions will be assu~med for coding: A phase transition 

in the transmitted signal causes a "0" to be input to the decoder, no 

transition causes a "1" to be input. 'The bit intervals are equally 

spaced for all bits. The code format lconsists of a single start bit of 

a "0" follcwed by the five data bits, followed by a single parity bit, 

ended by a single stop bit of a "1". 'The code is entered into the pager 

using SW200 where a switch closure is (a "1" and an open is a "0". The 

code will be stated as bit position 1 through 5 as noted on U200 from 

left to right. 

For additional reference, a listing of the pins and functions of U201 

is indicated in Table 2. 

The serial bit stream from pin 7 of U1103 is input to the Universal 

Asynchronous Receiver Transmitter (UAR'T) U201 into the receiver input, 

pin 20. The UART timing is controlled by quartz crystal Y200 and the 

divider strapping on pin 2 of U201. Tlhe UART separates the serial bit 

stream into the five parallel code bits and makes them available on 

pins 12 through 8 as noted on the sche~matic. In addition, parity and 

framing error outputs are made available on pins 12 and 14 respectively. 

A data ready strobe is provided on pin 19 which is reset by input to 

pin 18. The receiver outputs are not reset by pin 18, only the strobe 

is reset, so the data and the error outputs remain latched until the 

next code sequence of 8 bits is received (start, 5 code, one parity, 

one stop). 

Arthur D Little, Inc. 
The five parallel code bits are routed through the circuitry about U200. 

This IC and the code select Switch U200 permit selected code bits to be 

inverted. The programming is such that the correct code will produce 

all "1"s at the transmitter input to the UART, pins 26 through 30. 

The converted code pins from SW200 are loaded into the transmitter section 

of U201 by the data ready strobe from pin 19 to the load input pin 23. 

When the code sequence has been serially clocked out of the transmitter 

at pin 25, the empty output of the transimitter at pin 24 provides a 

receiver data strobe clear into U201 pin 18. 

The remainder of the logic functions as follows: The initial "0" start 

bit from the pin 25 transmitter output of U201 is ignored by the U202 

flip flop because of the pulse delay output from the buffer register 

empty output pin 22 of U201. If the remainder of the other code and 

parity pulses output from pin-25 have no high to low transitions U202 

will be clocked on through pin 11 and outputs to the alarm interface 

will be provided. Additional gating from the number one bit position 

at pin 5 of SW200 is provided into pin 9 of U203 to insure that the 

decoding only occurs if all the code outputs at SW200 are high (i.e. no 

low to high transitions plus number one bit high means all are high 

since the last stop bit is always high). Decoding will be inhibited 

by a framing or parity error on pins 13 or 14 of U201. 

A correct decoding sequence causes the "0" flip flop U202 to latch with 

pin 13 high and pin 12 low. The pin 12 output is routed to the LED 

driver Q200 and turns on the LED. The pin 13 output triggers U103B 

for an approximate 1 second interval determined by C116 and R123. The 

output of U103B at pin 9 feeds the aural alarm through the driver 

transis tor 4100. 

The alarm will sound only once and the LED will remain latched on until 

U202 is reset by SW100C. 

Arthur D Little, Inc. 
111. MANUFACTURING COST ESTIMATE 

The cost estimates for the individual assemblies that comprise the call 

alert system are attached as Appendix I and are based on our prototype 

design. Specific features of the prototype will not necessarily find 

their way into a production system, particularly in view of the test 

functions built into the transmitter. 

The cost estimates in Appendix I are based on the following assumptions: 

The call alert receiver will be manufactured in lots of 

one hundred units. 

The call alert transmitter will be manufactured in lots 

of ten units. 

This is factory cost; that is, the cost of materials 

and direct labor only. The labor costs include overhead 

for factory space and super~i~sion. We assumed an average 

of $12 per hour for all types of direct labor. 

a These prices do not include the cost of development, 

sales or administration. For a low-volume, job-shop 

type of manufacturing situation, which this is, the 

factory cost would be marked up 200-300 percent to get 

the sell, or list price. 

a The cost of production engineering and documentation 

is not reflected in these prices. Complete parts lists 

and fabrication drawings as well as the design of a 

printed circuit board for the call alert transmitter 

will be required before a production run of any size 

could be started. 

B. CALL ALERT RECEIVER 

Although printed circuit boards were used in the prototype design of 

this unit and their cost savings are reflected in the cost estimates 

in Appendix I, further cost reductions are possible by the elimination 

of custom fabricated parts. For instance, if the extensively modified 

Arthur D Little, Inc. 
commercial enclosure is replaced by a custom designed injection molded 

enclosure, and the purchased clip assembly is replaced by a custom 

designed aluminum die casting, then all the costs for fabricated parts 

would be eliminated. This would reduce the factory cost from approximately $167 to $125. If the antenna is produced on a semiautomatic 

coil winder instead of a laboratory type coil winder, then the factory 

cost would be reduced another $9. These construction and labor savings 

should be instituted before a significant production volume is started. 

C. CALL ALERT TRANSMITTER 

The transmitter will never be manufactured in as high a volume as the 

receiver, but it will still be cost effective to change from wire 

wrap construction to printed circuit wiring. This would eliminate the 

cost of I.C. sockets and component carriers as well as the labor costs 

for wire wrapping. The transmitter manufacturing cost would change from 

approximately $594 to $330. 

Arthur D Little, Inc. 
APPENDIX I 

COST ESTIMATES 

Arthur D Little, Inc. 
*1f manufactured in lots of 10. 

SOURCE 

- - 

- - - - - - - - 

*Factory Cost 

ITIN 

NO 

1 

2 

3 

4 

5 

6 

7 

QTV 

REQ 

, 

-- 

~WED BY DAT 

PART NUMBER OR 

IDENTlFVlNQ NWBER 

- -- 

--AP#)OVED BY - DATE /h Arthur D Little lnc CIy.(IIotx YISSICWU~TTs 021U) 

ELECTF#)NIC SYSTEMS SECTION 

NOMENCLATURE OR DESCRIPTION 

Enclosure and Panel (including labor to modify) 

Vector Board Assembly 

Components - - 

Labor to Assemble and Test - 

Switch Panel Assembly 

Components 

Labor to Assemble 

Battery 

I 

Misc . Components 

- -- - -- - 

Cost Estimate for Call Alert 

Transmitter 

TITLE 

PARTS LIST NUMBER : 79492 

-- - .. 

- -- - - . 

Misc. Fabricated Parts 

(Includes Labor to Manufacture) 

Final Assembly and Test Labor 

(Including Cable ~arness) -- 

- 

-- 

-- --- 

- -- 
c. 

O\ 

ITEN 

NO 

,I 

2 

3 

4 

SOURCE 

-- 

*Factory Cost, 

Call Alert 

OTY 

RE0 

, 

CART NUYIER OR 

IDENTlFYlMG NwwR 

-- 

-- - .. 

-- -- - -- 

1 

-C#PIAED BY- DATE 

NOMENCLATURE OR DESCRIPTION 

Enclosure (including labor to modify) _-- 

Components 

Fabricated Parts (including labor) - - 

Board #I1 Assembly -- - 

Components 

P. C. Board 

Labor to Assemble and Test 

Board #I2 Assembly 

Components 

P. C. Board 

Labor to Assemble and Test 

--- - 

- 

- - - - - 

Cost Estimate for A ArthurDLittlelnc 

CAMmIDCE WSI*CHULLTT1 0214a 

ELECTRONIC SYSTEMS SECTION 

-'AP~OVED BY p DATE - Receiver T I r_Lr 

PARTS LIST NUMBER : 79 49 2 z 

*If manufactured in lots of 100. 
APPENDIX - I1 

PARTS LIST - 

Arthur D Little, lnc. 
ITLM 

NO 

1 

QTY 

RE0 

- 

2 

1 

3 

CART NUMBER OR 

IDENTIFYING NUMBER 

Stainless Steel Backplate -. - - - -. . 

2 

2 

I 

NOMENCLATURE OR D ESCRlPTlON 

Stainless Steel Brackets 

Electronic Box EL-410 5 

I 

6 

7 

SOURCE 

mL 79492-22 

- -- 

Brass Standoffs, Cadmium Plated - 

- - 

Rose Enclosu

1 

BT1,2 8 

8 

I Lp = -185 mh, Cp-= 0.05 uf, Q = 30. 

1 -- 

ADL 79492-21 

- 

2 

9 11 

I - - -- 

-7 PI - Alarm AI-105 -- - - -- Projects Unli

Batteries B50T 

1 

Ev~rdv 

R1,R2 

CR3 

L1 

I I I I 

1.8K Resistors 1/4w 10% 

Antenna; 1" Long Coil, 2000 Turns !I32 Enamel Wire, 

Centered on 4" Long Permag Rod ilF125-1. 

I I I Enclosure Assembly 

CREPIRED BY DATE APPROVED BY DATE 

PARTS LlST 

A1 lpn Bradley 

LED MV5053 

m, 

Monsanto 

A ArthurDLittlelnc 

U~UIOCE USS*CHUSEWS O~I~O 

ELECTRONIC SYSTEMS SECTION - 

Call Alert Receiver T ITLL 

PARTS LIST NUMBER : 7 9 4 9 2 
lTtM 

NO 

1 

7 

3 

4 

5 

-6 

7 

8 

9 

-1 0 

-11 

12 

. 13 

14 

- 15 

16 

17 

-18 

-19 

70 

21 

22 

23 

24 

25 

QTV 

RE0 

4 

1 

1 

3 

1 

2 

1 

2 

1 

1 

-La1 

1 

2 

1 

2 

1 

3 

1 

CART NUMBER OR 

IOENTlFVlNG NUMBER 

, MEPIRED BY DATE -'APPROVED BY - DATE /h Arthur D Little, lnc CAYMIDGE uAsswnustm OZIW 

ELECTRONIC SYSTEMS SECTION 

NOMENCLATURE OR D ESCRlPTlON 

-- Cent ralab 

PARTS LIST 

Board ill Assembly Call Alert 

Receiver 

PARTS LIST NUMBER : 7 94 9 2 

SOURCE 

-- 0.0083pF Ceramic UK Series -- - I 

Allen Bradley 

- 

MEPCO 

MEPCO 

Allen Bradley 

Allen Bradley 

Allen Bradley 

coming 

Cent ralab 

Centralab 

Rll)n_1n7-1 I - n - - 

C103 

O~~J!F---~ Ceramic UK Series -- Centralab 1 

- - - - 

Rl Ql h 

C1 Oh 

Rl n? 

R104,122,124 

Rl05 

R106.133 

R107 

R108.110 

R112 

4 --+- C105,109,110,118 - 71 0.004 7yF Ceramic UK Series 

2 k106,107 OlpF -- -- Ceramic ZTK Series - -- --- Centralab -- --- 

R11? 

4 

v 

7 7K 

~108,111,112,115 Tantalum MZP Series 

OK 

1 01)~ 

1 OK 

17nK 

-- - 

411 fj - 

1IJF/IOY- - - -- 

I 

1 2116 -- - - -- - - - - . - -- - Tantalum EP Series -- - - -- - - 

R115 

R116.117 

R119 

R120.121 

ClOO 

C101,113,114 

F102 

1 ,"I17 

5K r,rhnnPil 

I n~ 

560K 11 11 

4 7K 11 11 

.022u~/35~ T-.P ws 

.0022uF - Ceramic UK Series 

.001pF - - Ceramic UK Series 

.10uF/15~ TantmP Series 
I 

CART NUMBER OR 

IDENTIFYING NUMBER NOMENCLATURE OR D ESCRlPTlON SOURCE 

UlOO CD4046AE -- RcA - - -- - - - -- 

~101,02 L144 \ 

I 

Siliconic 

U103 CD4098BE RCA 

ktorola 

-- Wilbrecht 

I I I 

1 I I 

-WED BV DATE AP~WED BY A Arthur D Little lnc l~oard #I Assembly Call Alert CMIMIOCE MAssunusms 071a 

-1 ELECTRONIC SYSTEMS SECTION ' 

Receiver 

PARTS LIST NUMBER 7 94 9 2 
SOURCE 

Allen Bradle

---Allen Bradle

ITEM 

NO 

1 

7 

OTY 

RE0 

10 

1 

Cnrninv 

Tn-i 1 

7 

8 

9 

10 

CART NUMBER OR 

IDENTIFYING NUMBER 

R200-206,208-209 

R710 

NOMENCLATURE OR D ESCRlPTlON 

lOOK 11th 10% pp - -- 

4 7n~ I I t t 

1 

7 

1 

I 

U203 

00,701 

0700 

00 

-- 

- 

- - - -- - - , 

-PIRED BY MYE - --APPROVED BY DATE A ArthurDLittlelnc 

CAYMIOGE Y*SYCUU~~S OZICO 

ELECTRONIC SYSTEMS SECTION 

TN44 54 

65 

Crystal, 1.0 MHz, TO - 5 Size 

-- - 

- 

- 

- - - 

I 

PARTS LIST 

Call Alert Pager 

T I TJ. 

PARTS LIST NUMBER. 79492 

RCA 

Mown1 a 

Re eves-Ho-fLm

Board /I2 Assembly 
ITEM 

NO 

1 

2 

3 

4 

5 

, 6 

7 

, 8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

18 

19 

20 

21 

,22 

SOURCE 

Allen Bradley 

w 

Allen Bradley 

Keme t 

Kemet 

l~ornell Dubli

Kemet 

Centralab 

THW 

TFW 

THW 

Keme t 

Motorola 

G.E. 

Motorola 

R.C.A. --- 

R.C.A. 

Of Y 

RE0 

1 

3 

CART NUMBER OR 

IDENT IFYING NUMBER 

R1 

R2,3,4 

NOMENCLATURE OR D ESCRIPTION 

~OA 1/4w - 10% -- Resistor 

-PARED BY- - MTE18 

1 

1 

1 

3 

2 

1 

1 

2 

1 

1 

3 

2 

1 

1 

1 

1 

2 

1 

/, 7u r(* RI 

-APPROVED BY - DATE - A Arthur D Little IK CM~IOCL YASYCHUS~~S 02140 

ELECTRONIC SYSTEMS SECTION 

A 

PARTS LIST r 

TlTL& 

PARTS LIST NUMBER : 7 949 2 

yr 

-- 

R5,7,9-14,16-20, 

25-29 

R6 

R8 

R15 

I 

llOOK 

2K 

24K 

470K 

R23.24 

C1 

C2 

C3,4 

C5 

C6 

C7,8,9 

C10,ll 

C12 

C13 

Q1 

Q2 -. 

Q3,4 

Q5 

Q6 

J R21,22,30 

lA 1/4w 10% 1 

10u~/35~, TAN. , T360 Series Capacitor 

1K 

22u~/35~, TAN. , ~360 Series 6 

600pF, MICA, DM15 " 

47uF/20~ T360 Series 

. luF/5OV UK t t 

~~~F,POLYCARBONATE, X483 Series 

3uF, POLY CARBONATE, X483 Series 

2uF, POLY CARBONATE, X483 Series 

1 

150u~/20~, TAN., T360 Series & - 

-- -- 

2N6109, PNP Transis tor 

2N3904, NPN 1\ 

MPSA05, NPN 

2~64 89,PNP - - - 

2N6486, NPN 4 

Call Alert Transmitter 
CART NUMBER OR NOMENCLATURE OR D ESCRlPTlON 

IDENTIFYING NUMBER 

31 

. 32 

,33 

34 

35 

-36 

37 - - 

38 

39 

40 

41 

1 U8 '1~6403 

Intersil 

- - 

-WED BY DAE 

Motorola 

- + 

-APPROVED BY DATE /h ArthurDLittle,lnc 

UYMIOCE YISSICMUY~S 02140 

ELECTRONIC SYSTEMS SECTION 

MC14576 7. 

PARTS LIST 

* 

Call Alert Transmitter 

TITLE -- 

PARTS LIST NUMBER 7 949 2 

KJU,12 

Motorola 

Cv~cficlr 

on 

ADL 79492-2

--- 

ADL 79492-2

ADL 79492-2

Globe 

-- - 

Ampheno 1 

MC14506B +# 1 U14 

18 

1 

5 

1 

1 

1 

1 

1 

-- - 

I.C. Sockets Wire Wrap 703-3898 - 01 - 03 - I h 

Vector Board 85674HE 

I. C. Component Carriers 3728-01-03-00 

Enclosure A- 10-N8P Hoffman Engineering 

Back Panel 6 1/4 x 8 1/4 Aluminum --- - 

Switch Panel 1 1/2 x 6 1/4 Aluminum -- -- 

- 

BTI ery 43 AH 12V 

- - - - -- - 

.% 3102A-20-20P 

- - - - - 

Connector Receptacle 
ITEW 

NO 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

54 

QTY 

RE0 

1 

10 

1 

1 

1 

1 

2 

1 

1 

1 

1 

1 

- - 

CART NUMBER OR 

IDENTIFYING NUMBER 

9760-20 

53-S12 

S1 

S2 

Y1 

T1 

- 

2802 

XF1 

F1 

- -- 

- - - - - - - . 

- 

NOMENCLATURE OR D ESCRlPTlON 

Cap and Chain Assembly - - - 

Switch SPDT Tonnle //71015YA 

Switch 3PDT Toggle 1/73015YA 

Switch 1/2*3509 7-1 

Crystal, 1.0 MHz, TO-5 Size - 

Transformer; Primary 10 Turns 1/32, 140 Turns 1/32: 

Secondary 2 Coils, 35 Turns 1/26 Each; Ferroxcube 

i/~M8- 3B 7 

Binding Posts 

Fuse Holder, HKP 

1 

Fuse 1 

Handle 

Mounting Bracket 

Phenolic Protector I 

Miscellaneous Hardware (Standoff's, Foam Pads) 1 

- 

-- -- 

- .--- --- - 

-- - - 

~MED BY DEE 

I 

I SOURCE 

Amphenol 

CXK TmC&K Inc. 

AMP 

Reeves-Ho f f m

ADL 

H.H. Smith 

Buss 

Buss 

ADL 

ADL 79492-01 

ADL 

ADL 

-- - -- 

--APPROVED BY - DATE A ArthurDLittle,lnc 

UYYlDGL YISWHUS(TTS 02140 

ELECTRONIC SYSTEMS SECTION PARTS LIST 

Call Alert Transmitter TlTLl 

PARTS LIST NUMBER. 79 49 2 
APPENDIX II[I 

VISUAL PAGER DILAGRAM 

Arthur D Little Inc. 
FIGURE 21 

I 

5 6 

a u + I