Uncontrolled Copy C olour N ot Supported

ELECTRICAL AND MECHANICAL 

ENGINEERING REGULATIONS 

(By Command of the Defence 

Council) 

RESTRICTED 

TELECOMMUNICATIONS 

C 742 

CLANSMAN AUDIO ACCESSORIES 

TECHNICAL HANDBOOK - TECHNICAL DESCRIPTION 

Errata 

Note: These Pages O-01 are to be filed immediately in front of Page 1, 

Issue 2, dated Feb 80. 

I. 

2. 

The following 

Page 5, Fig 1: 

amendments must be made to the* regulation. 

a. Receiver annotation: 

Delete: 'RECEIVER INSERT' 

Insert: 'RECEIVER INSET'. 

b. Circuit diagram, connection to PLA: 

(1) Pin A: 

Delete: 'Y' 

Insert: 'R'. 

(2) Pin D: 

Delete: 'R' 

Insert: 'Y' . 

3. 

4. 

5. 

Page 7, Fig 2, receiver annotation: 



Page 12: 

a. Main heading at top of page: 

Delete: ' STANDARD ' 

Insert: 'GEXRAL PURPOSE' 

b. Page 23, line 1: 

Delete: 'standard1 

Insert: 'general purpose' 


a. Fig title: 

Delete: 'standard' 

Insert: 'general purpose' 

Issue 1, Feb 80 (17N) RESTRICTED Page 0

TELECOMMUNICATIONS RESTRICTED ELECTRICAL AND MRWA!KtCAL 

C 742 ENGINEERING RXGULATIONS 

b. Microphone annotation: 

Delete: 'MICROPHONE INSERT' 

Insert: 'MICROPHONE INSET'. 

C. Receiver annotation: 



6. 

7. 

Page 14, para 27, line 1: 


Insert: 'general purpose'. 


a. Microphone annotation: 



b. Receiver annotation: 


Insert: 'RECEIVIZR INSET'. 

8. 

9. 

Page 16, para 34, line 1: 


Insert: 'general purpose'. 


a. Microphone annotation: 



b. Receiver annotation: 

Delete: 'RECEIVl3R INSERT' 

Insert: 'RHCEIVER INSET'. 

10. 

11. 

Page 19, Fig 8, receiver annotation: 


Insert: 'RFCEIVER INSET'. 

Page 20: 

Delete: ‘2896/Tels’ and 'END'. 

Page 01 RESTRICTED Issue 1, Feb 80



(By Command of the Defence 

Council) 

KFSTRICTED 

TEIXCOMMU-NICATIONS 

C 742 

I CONDITIONS OF DELkXSE 

CMSMAN AUDIO ACCESSORIES 

TECHNICAL HANDBOOK - TECHNICAL DESCRIPTION 

These Pages I-4 supersede Pages I-4, Issue 1, dated Aug 73. 

CONTENTS 

INTRODUCTION 

GENERAL .................................... 

EI;ECTRICAL PARM$llERS .............................. 

MECHANICAL PARAMmERS .............................. 

TESTING AND REPAIR FACIIJTIXS ........................ 

Para 

: 

4 

5 

HELMET-HEADSET, EIECTRICAL, 'A' VEHICLE CREWMAN'S HEADGEAR 

ROLE AND PURPOSE ................................. 6 

CONSTRUCTION ................................. 7 

DESCRIPTION ................................. 10 

BEADSET MICROPHONE, 'A' 

VEEICIE STAFF USERS HEADGEAR (AVSU) 

ROI;F; AJD PURPOSE ................................. 12 

CONSTRUCTION ................................. '13 

DESCRIPTION .................................... 16 

BEADSET MICROPHONE, 'B' VEHICIZ AND INFANTRY (BV and I> 


ZONSTRUCTION ................................. 18 

DESCRIF'IJION .................................... 19 

CABLE ASSEMBLY, SWITCH ELECTRICAL 

ROI;E AND PTJRFQSE ................................. 

CONSTRUCTION ................................. 

DESCRIPTION .................................. 

20 

21 

22 

HANDSET, GENERALPURPOSE 


CONSTRJCTION ................................. 24 

DESCRIPTION .................................... 25 

Issue 2, Feb 80 (17N) RESTRICTED Page I


C 742 

RESTRICTED 

EIECTRICAL AND MECHANICAL 

ENGINEERING RXGULATIONS 

Para 

HANDSET, REMOTE CONTROL 

ROLE AND PURPOSE . . . 

CONSTRUCTION . . . 

DESCRlPTION . . . 

. . . 

. . . 

. . . 

... ... ... ... ... ... 

... ... ... ... ... ... 

... ... ... ... ... ... 

. . . 

. . . 

. . . 

. . . 

. . . 

m.. 

. . . . 

. . . 

. . . 

26 

27 

29 

HANDSET, TANK TEIEPH0N.H 

ROLE AND PURPOSE 

CONSTRUCTION .-. 

DESCRIPTION 0.. 

. . . 

. . . 

. . . 

... ... ... ... ... ... 

... ... ... ... ... ... 

... ... ... ... ... ... 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

33 

34 

35 

SINGLF TRANSDUCER HEADGEAR ASSEMHLY 

ROLF: AND PURPOSE 0.0 

CONSTRUCTION 0.. 

DESCRIPTION . . . 

... ... ... ... ... ... ... 

... ... ... ... ... ... ... 

... ... ... ... ... ... ... 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

;i 

39 

RESPIRATOR MICROPHONE 

ROLE AND PURPOSE . . . 

CONSTRUCTION . . . 


... ... ... ... ... ... ... 

... ... ... ... ... ... ... 

... ... ... ... ... ... ... 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

40 

41 

42 

HHADSET MICROPHONE UK/PRC 349 

ROLE AND PURPOSE 0.. 

CONSTRUCTION 0.. 


... ... ... ... ... ... ... 

... ... ... ... ... ... ... 

... ....... ... ... ... ... 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

43 

44 

45 

Fig 

FIGURES 

Page 

1 Helmet-headset electrical, 'A' vehicle crewman's headgear 

Headset microphone (AVSU) ..................... 

: Headset microphone (BV and I) .................. 

4 Cable assembly, switch electrical ............... 

Handset, general purpose ..................... 

2 Handset, remote control ..................... 

Handset, tank telephone ..................... 

r3 Single transducer, headgear assembly ............ 

9 Respirator microphone ..................... 

10 Headset, microphone UK/PRC 349 .................. 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

. . . 

5 

; 

11 

13 

'15 

17 

19 

sz 

Page 2 RESTRICTED Issue 2, Feb 80

ELEYCTRICAL AND MECHANICAL UK RESTRICTED TELECOMMONICATIONS 

ENGINEERING REGULATIONS C 742 

INTRODUCTION 

Note... 

These 

5 has 

Pages 3-4, Issue 3 supersede Pages 3-4, Issue 2 dated Feb 80. P=a 

been amended. 

GENERAL 

1. The 

a. 

b. 

C. 

d. 

e. 

f. 

g- 

h. 

j. 

k. 

Clansman audio accessories consist of the following items: 

5965-99-620-3251 Helmet-headset, Electrical, 'A' Vehicle 

Crewmans Headgear. 

5965-99-620-5668 Headset Microphone (AVSU). 

5965-99-620-8320 Headset Microphone (HV and I>. 

5965-99-620-5667 Cable Assembly, Switch Electrical. 

5965-99-620-5669 Handset, General Purpose. 

5965-99-620-5670 Handset, Remote Control. 

5965-g+620-5672 Handset, Tank Telephone. 

5965-99-622-5436 Single Transducer Headgear Assembly. 

5965-99-622-5437 Respirator Microphone. 

5965-99-643-7935 Headset Microphone, UK/PRC 349. 

2. With the exception of the electrical and mechanical parameters, and 

testing and repair facilities, this regulation describes each audio accessory 

seperately and is therefore, sectionslized in the order shown in Para I. 

ELECTRICAL PARAMETERS 

3. Microphone impedance: 300 + 60 8 with 10 mV at 1 kHz connected across 

the Microphone. 

Receiver impedance: 300 + 60 Q at 1 kHz. 

Power supply (Remote 

HandsetandTank 

Telephone Handset): 18 V to 32 V d.c. 

MECHANICALPARAMETERS 

4. The lightweight microphone insets are of the pressure gradient (noise 

cacelling) type, whilst the receiver insets use smell rocking armatures. 

Cable connections within the audio accessories are terminated by push on 

connectors. 

TESTING AND REPAIR FACILITIES 

5. Failure diagnosis can be carried out using the Test Set, Audio Radio 

Accessories or a multimeter, whilst functional testing is achieved by 

connecting the headgear to a known good radio set or control harness, or by 

using the Test Set, Audio Radio Accessories. 

Issue 3, Jan 84 (ITN) UK RESTRICTED Page 3

TELECOMMUNICATIONS UKRESTRICTE33 ELECTRICAL AND MECHANICAL 

C 742 ENGlINEZXING REGUWITIONS 

I-ELMEZ- 

HEADSET ELECTRICAL, 'A' VEHICLE CREWMANS HEADGEAR (Fig I> 


6. The Helmet - Headset Electrical, 'A' Vehicle Crewtnans Headgear is 

designed for use in AFV installations fitted with Larkspur II or Clansman 

radio control harness. The headgear provides hands free microphone operation, 

protection against and exclusion of ambient noise and bump protection for the 

head. 

CONSTRUCTION 

7. The receiver insets are mounted in foam padded ear defenders. The ear 

defenders are fitted with adjustable accoustic valves which provide 

protection against external noise when closed, whilst allowing normal 

conversation when open. The receiver assemblies can be adjusted for vertical 

positioning over the ears. 

8. The microphone and boom assembly is attached to the right hand side of 

the helmet. The assembly incorporates a socket for the respirator microphone 

which, when connected, automatically inhibits the boom microphone. The boom 

is pivoted to permit positioning of the microphone to suit the users requirements 

and may be locked in the optimum position. 

9. An internal cats cradle and detachable foam pads fitted to the browline 

and neckline provide adjustments which allow each helmet to be fitted to suit 

the individual wearer. 

DESCRIPTION 

10. In normal use, the headgear is connected, via the Cable Assembly, Switch 

Electrical, to either a harness box or radio. The two receivers are 

independently wired, the left hand receiver being connected between pins D 

and E of plug PLA and the right hand receiver between pins G and E. 

Il. The boom microphone circuit includes the series resistor RI, the output 

being taken from pins A and B of plug PLA. When the respirator microphone 

(Fig 9) is connected to socket SKA, pins B and C are shorted together 

thereby inhibiting the boom microphone. The respirator microphone is 

connected between pins A and B with resistor RI connected in parallel. 

Page 4 UK RESTRICTED Issue 3, Jan 84

l!LExTRIcALANDMEcRAN1cAIl REElYRICTED !PEIXCOMMUNICATI~NS 

ENGIlllEERING REXXUTIONS C 742 

Kate: These Pages 5-6 supersede Pages 5-6, Igsue l.dated Aug 73. Fig I has 

been revised. 

SHELL 

VELCRO 

RETAINER 

CABLE 

(3 OFF) 

INNER CROWN PAD 

INTERNAL 

CABLE 

ACOUSTIC 

DAMPER 

LOCKING 

NUT 

EARSHELL ASSY (L .H) 

SELF ADHESIVE 

RUBBER PAD 

BOOM 

ASSY 

BASE 

RECEIVER 

INSERT 

VELCRO STRAP IRH) 


SOCKET SKA 

MAIN CABLE ASSY- 

CABLE ENTRY 

HOUSING 

CHINSTRAP 

SKA 

VIEW ON REAR 

R.H SIDE 

w 

I 

L 

MC AND BOOM ASSY 

----s-v -I 

VIEW ON FRONT 

OF PLA 

SNATCH 

CONNECTOR 

PLA 

2896119 

VIEW ON FRONT 

OF SKA 

Fig 1 - Helmet, headset electrical, 'A' vehicle crewman's headgear. 

Issue 2, Sep 79 (17N) RESTRICTED Page 5

TELJ3COMMlJNICATIONS 

C-742 


RELSTRICTED 

HEADSEI' MICROPHONE (AVSU) 

ZUXTRICAL AND MECHANICAL 

ENGINEERING RETJULATIONS 

12. The headset microphone (AVSU) is designed for 

by personnel other than crewmen. 

use in AFV installations 

CONSTRUCTION 

13. The headset consists of two receiver assemblies with a microphone and 

boom assembly attached to the right-hand receiver. 

14. The receiver insets are mounted in foam padded ear defenders fitted 

with variable acoustic valves. A socket for the respirator microphone is 

fitted to the right-hand earshell assembly. The boom is pivoted to allow 

positioning of the microphone and may be locked in the optimum operating 

position. 

15. Adjustable straps and padded bands assist in fitting the headset to 

the individual wearer. 

DEXXIPTION 

16. The headset is normally connected to a harness box or radio via the 

cable assembly, switch electrical. The headset microphone (AVSU) is 

electrically identical to the helmet-headset (paras IO to 11 refer). 

Page 6 STRICTED Issue 2, Sep 79

33.XCTiUCAL AND l@XXANICAL 

ENGDlDZRR?G FBGUUTIONS 

ElEsTRlCTgD 

TKLBCOMMJNICATIORS 

c 742 

MICROPHONE 

y--~sTRAp 

I 

ACOUSTIC DAMPING PADS 

KNURLED 

LOCKING NUT - 

J f;l 7Jj--- RECEIVER INSERT 

ACOUSTIC 

VALVE 

\ RESPIRATOR MICROPHONE 

‘

TELEGOMKJNICATIONS 

c 742 

RESTRICTED 


ENGlINEEEING RF&lLATIONS 

HEADSET MICROPHONE (BV AND I) 

ROLEANDPURPOSE 

17. The headset microphone (BV and I) is designed for use with infantry 

operated radios which may be man-pack or vehicle mounted. 

CONSTRUCTION 

18. The headgear is of lightweight moulded plastic construction. The 

earshells are foam padded for user's comfort. The microphone and boom 

assembly, respirator socket and cable assembly -are all m,ounted on the lefthand 

earpiece assembly, whilst the right-hand earphone assembly is detachable 

from the earpiece and designed as a *throw-away' item. 

DEXCRIPTION 

The headset microphone (EV and I) is electrically identical to the 

iz; vehicle crewman's headgear described in para 10, except for the 

electrical contacts of the right-hand earphone assembly. These comprise 

two brass studs which engage with two brass springs in the earshell assembly, 

the earphone assembly being retained and secured in position by a clip and 

strap. 

?age 8 REzrR1cTED Issue 1, Aug 73

ELECIXICALANDME~ICAL RESTRICTED TELECQMMUNICATIONS 



These Pages 9-10, Issue 2 supersede Pages g-10, Issue 1 dated Aug 73. 

The information has been updated. 

HEAOSTRAP 

ASSEMBLY 

(L.H.) 

INTED CIRCUIT 90ARD 

R.H. RECEIVER 

INSET 

R.H. EARSHELL 

NOTE POSITION 

OF CAM 

+I++~, i L.H. ’ 

VIEW ON FRONT 

Of PlA 

A0 

80 OC 

VIEW ON FRONT 

ON 

5KA 

2896/132 

Fig 3 - Headset microphone (BV and I) 

Issue 2, Aug 82 (17N) RESTRICTED Page 9


C 742 

RESTRICTED ELECTRICALAND MECHANICAL 


CABLE ASSEMBLY, SWITCH ELECTRICAL 


20. The cable assembly, switch electrical is used to connect the appropriate 

Clansman headgear to the harness, radio or associated equipment. The pressel 

switch for the headgear is contained in the pressel box. 

CONSTRUCTION 

21. The box comprises a lever operated pressel switch contained in a 

rectangular plastic moulded case. A spring clip, fixed to the case, allows the 

box to be clipped to the operators clothing. The coiled cable is fixed to 

the box through a sleeve and gland nut, whilst a strain cord secured inside 

the box prevents the cable being pulled through the sleeve. Connections 

inside the pressel box are made by push-on connectors. A %-way socket is 

fixed to the main assembly and protrudes through the pressel box cover where 

it is secured by a hexagonal nut. A pre-set Live Mic switch, operated by a 

slotted-head screw, can be set to provide 'hands-free' operation when the 

cable assembly, switch electrical is connected to a harness box with LIVE IC 

facility. 

DESCRIPTION 

22. Items of Clansman headgear are connected to the cable assembly, switch 

electrical, which in turn is connected to a harness box, radio, or audio 

equipment at sockets labelled AUDIO or HEADGEAR. When used with the control 

harness, the cable assembly, switch electrical can be by-passed by the 

selection of LIVE IC (see Tels L 802, Table 6). 

Page 10 RESTRICTED Issue 2, Aug 82


ENGINEEXING REGULATIONS 

TELECOMKUIiICATIORS 

c 742 

CONNECTOR AND 

LEAD ASSEMBLY 

PRESSEL 

S2 CONTACTS BAR ASSEMBLY 

LIVE MIC 

\ r/ 

ACTUATING SCREW 

I 

I 

HEXAGONAL 

SECURING 

I 

NUT 

KNURLED 

SECURING 

NUT 

SCR;EN 

STRAI; CORD Pi?ESSEL SWITCH 

ANCHOR POINT ASSEMBLY Sl 

COVER 

PLUG 

PLA 

PLA 

A *-(- 

I 

I 

R 

LL 

WA 

I 

I 

SKA 

VIEW ON FRONT 

OF PLA 

I 

I 

F --(- 

BK 

II 

SlB 

I 

VIEW ON FRONT 

OF SKA 

2896/22 

RED 2:l 

fig 4 - Cable assembly, switch electrical 

Issue 1,Aug 73 RFJsTR1cTED Page 11

TJZLFCOMMUNICATICNS 

c 742 

RExxrR1cTED 

ELEXXRICAL AND MECHANICAL 

ENGllEEZING REClJLATIONS 

RANDSFT,STANDARD 

ROLEANDPURPOSR 

23. The handset, standard is a conventional hand-held telephone type handset 

used to operate individual radios. 

CONSTRUCTION 

24. The handset comprises a black plastic body containing microphone and 

receiver insets, a pressel switch and a p.c.b. assembly. All wiring connections 

are made on the p.c.b. which is accessible by removal of a cover 

plate. The pressel switch is operated by a lever which is recessed into 

the body to give a measure of protection against-accidental operation. A 

clothing clip is secured to the handset body. Connections to the handset 

are made by a cable assembly which is passed through the cable entry plate 

and secured by a sheath and gland nut. A strain cord is secured inside the 

handset body. 

DESCRIPTION 

25. The receiver inset is permanently connected into circuit at pins D and 

E of plug PLA, whilst the microphone inset is connected into circuit by one 

pole of the pressel switch. The remaining pole of the pressel switch is 

used to connect pins E and F together and activate the transmit function in 

the radio. 


ELBCTRICALAND-ICAL 

I4TGINEERING RERJLATIONS 

RESTRICTED 

Txzac~IcATxoHs 

c 742 

STRAIN 

ANCHOR 

\ 

SB 

SA 

- - 

3 - - 

PRESSEL 

BAR 

1 

SWITCH / 

ASSEMBLY 

CABLE 

PLATE 

ENTRY 

CABLE 

ASSEMBLY+/ 

TOR 

ETNEC 

PLA 

B- 

I 

G 

I 

i 

VIEW ON FRONT 

OF PLA 

2896123 

2: I REDUCTION 

fig 5 - Handset standard 

I&sue 1, Aug 73 page 13


c742 

RESTRICTED 

E;LBcTRICALAND~ICAL 

EKG-G RECULU‘IONS 

HANDSET, I3iExYm CONTROL 

26. The handset, remote control enables a Clansman radio to be remotely 

operated up to a distance of 3 Ian using DlO or 5 km using one pair of CTlO. 

CONSTRUCTION 

27. The handset is of similar construction to the handset, standard with the 

addition of a call switch and a thin film amplifier which, together with its 

associated components, is mounted on a p.c.b. 

28. The call switch and two insulation piecing cable connectors are mounted 

on the connector plate assembly. A clothing clip is secured to the handset 

body. 

DESCRIPTION 

29. The remote handset is connected to the remote terminals of the apprcpriate 

Clansman harness box or radio by a 2-wire field cable, connection 

being made by the two insulation piercing connectors on the body of the handset. 

30. With the handset connected correctly to the harness or radio, a +ve 

voltage is applied to pins 9, 10 of module Xl and to the 27V zenor diode Dl. 

Under normal circumstances, Dl does not conduct and the current flow in the 

remote loop is governed by the output impedance of module Xl. This impedance 

maintains the Clansman radio in the receive condition. Should the remote 

lines be incorrectly connected, Dl conducts and the current flow in the remote 

loop exceeds 15mA. This current represents the 'call* condition and the 

Clansman equipment produces the 2Mz call tone. 

31. To transmit, the pressel switch SA is operated thereby connecting the 

microphone across the amplifier input. The impedance presented by the handset 

produces a current of from 8-l%n~ to the Clansman equipment, which 

represents the transmit condition. Audio signals from the microphone are 

amplified and passed to line, and the earphone connected across the line 

connectors provides sidetone for the remote operator. 

32. Operation of the CALL switch physically moves a small p.c.b., on which 

is mounted a 1OP resistor, so that it is placed across the line connectors. 

The current flow in the remote loop exceeds 15mA, and the Clansman equipment 

generates the call tone. 


ELEXTRICALANDMECHANICAL 

ENGINEERING REXULATIONS 

KESTRICTED 

TELEC=ICATIC 

c 742 

I 

RECEIVER 

INSERT 

BODY 

COVER, 

PRINTED 

CIRCUIT 

BOARD 

- PRESSEL BAR 

ASSEMBLY 

CONNECTOR 

ASSEMBLY 

PLATE 

MICROPHONE 

-T /INSERT 

CALL 

BUTTON y 

Y 

INSULATION PIERCING 

CONNECTOR ( 2 OFF) 

r --------- 

I 

i . 

L -- 

0 

p696/2L 

RED 2:l 

Fig 6 - Handset, remote control 

Issue 1, Aug 73 RESTRICTED psge 15


c 742 

RESTRICTED 

ELEZCRICALANDMECHANICAL 

ENGINEERING REXULATIONS 

HANDSET, TANK TELEFHONE 


33. The handset, tank telephone is designed for use with *A' vehicle tank 

telephone installations to provide intercommunication with *A' vehicle crew 

members from outside the vehicle. 

CONSTRUCTION 

The handset is of similar construction to the handset, standard (pera 

with the addition of an integral amplifier of the type used in the handset, 

remote control (para 27). 

DESCRIPTION 

35* The connecting cable from the 'A' vehicle telephone box is taken to 

the handset through a cable entry plate. This cable has no strain cord, but 

relies upon a securing gland in the entry plate to prevent damage due to 

undue strain. 

36. The blue and red conductors have whipped loops which are secured inside 

the handset body at two screw terminals. The green and white conductors 

are terminated in crimped tags, each of which fits into a small terminal 

block fitted one each side of the p.c.b. The tags are secured to their 

respective blocks with a slot-head screw. 


ELECTRICALANDMECEAl?ICAL 

WGINEEBING REGULATIONS 

IXESTRICTED 

Tli3J3COMMUNICATIOfl4 

c 742 

RECEI VER 

INSERT 

TAG SECURING CLAMPS 

LOOP 

SECURING 

SCREWS 

PC0 

PRESSEL 

BAR 

SWITCH ASSEMBLY 

TANK TELEPHONE 

CORDAGE 

-4 

MICROPHONE INSERT 

0. 

2H-L - - 

3 - - 

- - 

w 

0 

COLOUR 1 SYMBOL_ 

GREEN G 

BLACK BK 

BLUE B 

,RED R 

,ORANGE 0 

WHITE W 

,BROWN BN 

2696/25 

RED 2 1 

Kg 7 - Handset tank telephone 

Issue 1, Aug 73 

RESTR1cTEa 

Page 17

TELECOMMUNICATIONS RESTRICTED ELECTRICAL AND MECHANICAL 

c 742 

ENGllGXRIl?G REGULATIONS 

SINGLE TRANSDUCERBEADGEARASSEMBLY 


37. The transducer assembly is connected to a radio, control harness box or 

associated audio equipment, and may be used either as a receiver or as a 

microphone. 

CONSTRUCTION 

38. The assembly is connected by a 6-wsy light flexible cord terminated by 

a 7-pt audio connector, internal connections are by push-on connectors. The 

transducer assembly comprises a standard receiver inset in a circular rubber 

container provided with a push-button pressel switch. An adjustable head 

harness allows the receiver to be fitted over one of the operator's ears. A 

strain cord prevents undue strain on the connector. 

DESCRIPTION 

39 l 

On receive, the element is connected between pins D and E of the audio 

connector. Operation of the pressel switch breaks the connection to pin D 

(AF) and connects pins A and F into circuit. Pin F is connected to pin E to 

effect send/receive change-over in the Clansmen equipment. Pin A (MIC) is 

connected to the secondary of a microphone transformer, the primary of which 

is connected to the earpiece now acting as a microphone. The two resistors 

in the primary circuit provide the necessary impedance matching. 

Page 18 RESTRICTED Issue 1,Aug 73

ELECTRICAL AND MECHANICAL UK RESTRICTED TELECOMMUNICATIONS 



These Pages 19 and 20 supersede Pages 19 and 20 Issue 

Fig 8 has been amended to show the 'Striker Plate'. 

1 dated Aug 73. 

HEAD HARNESS 

RECEIVER INSET \ - 

P.C.B. STRAIN PRESSEL 

CORD 

SWITCH 

PLA 

VIEW 

fROWT 

of ru 

DN 

rRCfSE1 

RECEIVE 

SWITCH 

POSITION 

289613 1 

Issue 2, May 87 (17~) 

Fig 8 - Single transducer headgear assembly 

UK RESTRICTED 

Page 19

TELECOMMLJNICATlONS 

IJR RESTRICTED ELECTRICAL AND MECHANICAL 

C 742 ENGINEERING REGULATIONS 



40. The respirator microphone replaces the boom microphone of the Clansman 

headgear when an operator is wearing a Respirator Anti-gas No S6. 

CONSTRUCTION 

41. A standard earpiece is used as a microphone, connections being via a 

6-way cord terminated in a 3-way plug. The microphone clips on to an 

adaptor ring fitted to the present respirator No S6 and will fit directly 

over the voice tube of the modified respirator No S6 to be introduced into 

service. 

DESCRIPTION 

42. When plugged into the headgear respirator microphone socket, the 

microphone is connected across a resistor, which, together with the series 

capacitor, compensates for any accoustic resonance and excessive 

sensitivity. The boom microphone is inhibited (para 11 refers). 

GREEN 

II 

II 

O.L7y 

WHITE 

4, 

I 

CL?- 

ORANGE 

I 

Fig 9- Respirator microphone 

Page 20 UK RESTRICTED Issue 2, May 87

ELECTRICAL AND MECHANICAL RESTRICTED TELl!COMMUNICATIONS 

ENGINEERING REGULATIONS c 742 

Note: These Pages 21 and 22 are to be filed immediately after Page 20, 

Issue 1, dated Aug 73. This information is additional. 


HEADSET MICROPHONE, uK/pRC 349 

43. The equipment is designed for use with the UK/PRC 349 manpack radio. 

CONSTRUCTION 

4-b* The assembly consists of a single receiver inset, a throat microphone 

and a pressel box. A head harness allows the receiver to be fitted over one 

of the operator's ears, and the throat microphone is held in place by 

elasticated straps. The presselbox is fitted with a clothing clip. 

DESCRIPTION 

45 ’ On receive, the receiver inset is connected between pins D and E of 

the audio connector. On operation of the pressel, pin F is connected to 

pin E to effect sena/receive changeover in the radio. The microphone 

(connected between pins A and B)is then connected to the audio input 

circuits in the radio. 

Issue 1, Feb 80 (1 iT?) RESTRICTED Page 21


c 742 

RESTRICTED 

ELEZTRICALAND MECHANICAL 


HEAD 

HARNESS 

VIEW ON FRONT 

-- -. . 

OF PLA 

NECKSTRAP 

CLOTHING 

CLIP 

2896/121 

2896/Tels 

Fig 10 - Headset microphone UK/PRC 349 

END 

Page 22 

RESTRICTED Issue 1, Feb 80

Uncontrolled Copy C olour N ot Supported

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?