Clear-Com RM-120A Instruction And Service Manual

RM-120A

Speaker

Station

INSTRUCTION

and

SERVICE

MANUAL

I|1

JI

II

Clearm

orm

Intercom

Systems

945

Camelia

St.

Berkeley,

California

94710

510-527-6666

Clear-Com

810031

8/15/88

REV.

C

CLEAR-CON

RM-120A

SPEAKER

STATION

OPERATION

MANUAL

TABLE

OF

CONTENTS

Section

Page

#

I

Introduction

to

the

RM-120A

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

1

II

Headsets

and

Mics

...........

2

III

Installation

...........

3

IV

operating

Controls

&

Connector:3

...........

4

V

Specifications

...........

7

VI

Parts

Listing

...........

8

Illustrations

Headset

Extension

Cord.

2

RM-120A

Rear

Panel.

3

Daisy-Chain

Interconnection.

3

RM-120A

Front

Panel.

4

RM-120A

Schematics.

9

NOTrcr:

While

Clear-Con

makes

every

attempt

to

maintain

the

accuracy

of

the

information

contained

in

its

product

manualS.

the

information

is

subject

change

without

notice:

DOCUMENTATION

ADDENDUM

4*

RM-120A

MANUAL

*

*4

REV.A

44

at

sNovember

17,

1987

*

4*

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*

4

4*

4*

4t W*

44

4

*t

*J

*

4

41.4

14 $sst

*J ****$**i*

4

X

*

44

.

4

* *

$*s**

MIC

TO

LINE

GAIN

LEVEL

INCREASE

In

effecting

a

4dB

Mic

to

Line

increase

in

gain

level,

the

following

changes

have

been

made:

Change:

At:

To:

100K

OHM

R50,

R51

220K

OHM

1.5K

OHM

R2

3

2.77K

OHM

I.

INTRODUCTION

TO

THE

RM-120A SPEAKER STATION

The

RM-120A

is a

remote

speaker

RM-120A

provides a Call

button

to

station

that

allows

selectable

com-

signal stations

on

the

channel(s)

municating

in

the

Clear-Com

System. chosen with

the

"Channel

Select"

The

operator

can

talk

and

listen

on

toggle

switch. Each channel

has

a

Channel

A,

Channel

B,

or

both

at

lamp

to

indicate

incoming

signals,

once (without

tying them together).

regardless

of the

Channel

Select

switch

position.

The

RM-120A

mounts

in a 19"

rack,

using

just

1.75"

vertical

space.

The

RM-120A

sidetone control allows

It

features a wide frequency

re- the

operator

to

adjust

the

level

of

sponse

speaker

and

operates

with

a

his/her

own

voice

as

heard

in

the

carbon headset

or a dynamic

head-

station's

headset/speaker.

Side-

set/telephone-style handset.

tone

control

helps

to

prevent acou-

stic

feedback

when

using

the

spea-

The

rear panel

provides a 1/4"

jack ker

and

gooseneck

mic

simultaneous-

for

output

to

an

external

speaker

ly.

You

need

only

adjust

sidetone

(using

it

disconnects

the

internal

when

you

set

up the

system

(if at

speaker).

The

operator

can turn

all),

not

when

other stations

join

down

the

volume

of

the

built-in

or

or

leave

the

intercom system.

external

speaker

to

have a private

conversation with a headset.

Al-

The

RM-120A

provides

excellent

ternately,

the

gooseneck

or

headset

speech

intelligibility

in

all

sur-

mic can

be

turned

off

to

use

the

roundings.

It

features

"Automatic

RM-120A

for

"listen-only"

(paging).

Headset

Detection," which

shuts

off

the

mic preamp

when a headset

is

The

RM-120A

provides a balanced

not

plugged

in.

This

prevents

program

input

for

monitoring

exter- noise

pick-up

on

the

intercom

line

nal

audio

in the

speaker

or

head- from

the

unused connector.

The

RM-

set.

The

RM-120A

mixes

the

pro-

120A also

incorporates a mic

limi-

gram with

the

intercom

signal

for

ter,

which

assures

constant

talk

monitoring

in the

headset

and/or

levels and

prevents

overload.

speaker.

The

station

provides

sep-

arate

controls

for

adjusting

inter-

Gooseneck

Mic

Option

com

and

program

volume

levels.

The

RM-120A

is

available

with

a

noise-cancelling

electret mic

on

a

The

"Stage

Announce"

feature

is

for

flexible

gooseneck.

Though

perma-

paging applications.

The

RM-120A

nently

attached,

the

length

of

the

provides a balanced,

line-level

gooseneck

is

field-adjustable.

The

output

signal

to a 1/4"

phone jack

electret

element

has

unusually

high

(on

the

rear

panel). The Stage

immunity

to

ambient

room

noise and

Announce

button

on

the

front

panel speaker

feedback,

thus

permitting

activates

this

output,

giving

the

practical

"hands-free"

operation.

operator

access

to

an

external You

activate

the

mic

by

setting

the

speaker/amp

system.

Pressing

Stage

Mic

On/Off/(On)

switch

to

"(On)"

Announce

mutes

the

operator's

voice

(momentary

on),

which

attenuates

to

the

intercom channels.

the

speaker

by 6 dB

to

reduce

the

possibility

of

feedback.

Visual

Signalling

is a

standard

Clear-Com

feature. The

"Call"

but-

The

RM-120A

provides

two

3-pin,

XLR

ton

attracts

the

attention

of

in-

connectors

for

each

channel

(4

tercom

users

who

have

removed

their

total;

two

inputs,

two

extensions).

headsets

or

turned

off

their

spea-

Standard two-conductor, shielded

kers

(it

can

also

activate

remote

mic

cable

connects

the

RM-120A

to

control

of

KB-112

Stations).

The

the

intercom system.

II.

HEADSETS

AND

MICS

The

RM-120A

provides:

To

assure

proper

level

and

perfor-

mance,

the

dynamic

headset

should

4

--

one

1/4"

phone jack

for

a

stan-

have

the

following

characteristics:

dard

carbon

headset,

AND

mic

Impedance:

150-250

ohms

--

one

4-pin,

male,

XLR

connector

Nominal

Output

Level:

-55

dBv

for

dynamic

headset,

telephone

Headphone

Type:

dynamic

handset,

or

push-to-talk

mic.

Impedance:

300-2000

ohms

NOTE:

If

you

simultaneously

use

a

The

RM-120A's

built-in

headset

amp-

carbon

headset

and

a

dynamic

head-

lifier

can

drive

a

headset

to

le-

set,

the

level

in

the

carbon

head-

vels

greater

than

110

dB

SPL, and

set

drops

audibly.

drives

two

dynamic

headsets

with

only

a 3

dB

reduction

in

level

when

Carbon

headset connections:

connected

with

the

proper

"Y"

cord.

Ring-----Headphone

Tip------Mic

Sleeve---Ground

It's

easy

to

make

an

extension

cord

for

your

dynamic

headset.

For

the

To

assure

proper

level

and

perfor-

cable,

we

recommend

Belden

8416

or

mance,

the

carbon

headset's

mic

the

equivalent

(2-conductor,

25-

impedance

should

be

50

ohms,

and

gauge)

or

Belden

8734

or

the

equi-

earphone

impedance

should

be

300-

valent

(3-conductor,

22-gauge).

2000

ohms.

See

the

diagram

below.

The

cord

length

should

be

15

feet

or

less;

Dynamic headset

connections:

anything

longer

might

lead

to

capa-

Pin

1----Mic

Ground

citive

coupling

between

mic

sig-

Pin

2----Mic

Hot

nal

and

headset

signal,

causing

Pin 3----Headphone

Ground

oscillation

or a loss

in

frequency

Pin

4----Headphone

Hot

response.

Caution:

Do

not

connect

mic

ground

and

headphone

ground

together.

Figure

1:

Headset

Extension

Cord

15

OR

LESS

NoTe

Heaosel

eaos

o0

noi

nave

to

De

shiecea

on

BelDen

8734

51A4FLDEDPAIR

BELDEN

8416

PIN

1:

MIC

GROUND

CAUTION:

DO

NOT

CONNECT

PIN

2:

MIC

HOT

MIC

GROUND

&

HEADPHONE

PIN : HEADPHONE

GROUND

GROUND

TOGETHER

Pin

4:

HEADPHONE

HOT

2

III.

RN-120A

INSTALLATION

The

RM-120A

connects

to

the

intercom

system

via

two

pairs

of

3-pin,

XLR

0

connectors

on

the

rear

panel.

1)

Route

each

channel

on a separate,

two-conductor,

shielded

mic

cable

(e.g.

Belden

8413)

from

the

Main

Station

intercom

output

connectors

to

the

rack

location

of

the

RM-120A.

2)

Rack-mount

the

RM-120A

and

then

apply

the

intercom

inputs

to

the

appro-

priately

labelled

(Channel

A

or

Channel

B)

3-pin

female

connectors

(on

the

rear

panel).

The

3-pin

male

connectors

provide

a

hard-wired

loop-through

for

each

channel,

which

allows

extension

("daisy-chaining")

of

the

intercom

lines

to

other

stations

in

the

system.

The

pin

assignments

for

all

intercom

connectors

are:

Pin

1:

Common

Pin

2:

+30

VDC

Pin

3:

Intercom

Audio

CHASSIS

OEPTH

Ch.

A

or

B

6.62'

S7vl3

t t 1 t A g

eor(Om.

3)

Program

Input:

the

RM-120A

rear

panel

contains

a

3-pin

female

connec-

tor

for

input

of a balanced,

line-level

auxiliary

input.

Pin

1 is

ground,

and

Pins

2

and

3

are

hot.

The

program

input

is

transformer-coupled;

it

will

also

accept

an

un-

balanced

input

if

you

ground

either

of

the

hot

leads.

A 0

dB

signal

will

drive

the

headset/speaker

to

full

output.

The

impedance

of

the

program

input

is

l0k

ohms

bridging.

The

program

audio

mixes

with

the

intercom

audio

(in

the

station's

headset

and

speaker

outputs

only),

and

the

listen-levels

of

each

are

adjustable

via

the

RM-120A

front

panel

controls.

4)

Stage

Announce

connection

from

rear panel:

output

to

speaker/amp

paging

system

(600

ohms

impedance);

ring/tip/sleeve

connections.

RM-120A

RM-120A

RM-120A

&

ii

ORB

I

Lig

I |

ARB

QE3

|

CH.

A

|

CH,

B>IIIPT

I

XESO

INTERCOM

OUTPUT

STANDARD

2-COND.

FROM

MAIN

STATION

SHIELDED

MIC

CABLE

DAISY-CHAIN

INTERCONNECTION

3

IV.

Rm-120A

OPERATING

CONTROLS

&

CONNECTORS

The

RM-120A

controls

and

connectors

are

described

below

in

the

order

in

which

they

appear

on

the

FRONT

PANEL

from

LEFT

to

RIGHT.

Fo

r

~~~~~~~~~~RM.120A

©

¾

==

=©

-f]H

;44'

2i

1,

0

0

00

-°

O

Jp

1900

-48260)

Call

The

Call

push-button

activates

visual

signalling.

It

allows

the

inter-

com

user

to

attract

the

attention

of

operators

who've

removed

their

headsets

or

turned

off

their

speakers.

The

Call

button

can

also

con-

trol

the

speaker

or

mic

at

KB-112

Stations

set

up

for

remote

control.

The

Call

signal

follows

the

position

of

the

"Channel

Select"

switch;

if

you

using

Channel

A,

the

Call

button

causes

the

lamps

to

light

at

all

other

stations

using

Channel

A

(and

likewise

for

Channel

B).

When

the

Channel

Select

switch

is

set

to

"both,"

the

lamps

at

all

stations

on

both

channels

shine

simultaneously.

The

Call

signal

is

active

for

as

long

as

you

keep

your

finger

on

the

Call

button.

Receiving

Signals:

The

amber

Call

lamp

on

the

left,

for

Channel

A,

lights

when

any

station

on

that

channel

activates

the

Call

circuit.

The

amber

Call

lamp

on

the

right,

for

Channel

B,

lights

up

when

any

Channel

B

station

activates

Call.

They

operate

independently

of

the

setting

of

the

Channel

Select

switch.

Note:

an

internal

jumper

reverses

the

Call

function

for

use

with

KB-112

remote

control--

call

Clear-Com

for

info.

Channel

Select

This

3-position

toggle

switch

assigns

the

RM-120A

speaker/headset

moni-

toring

function

to

(1)

Channel

A,

(2)

Channel

B,

or

(3)

both

channels

(RM-120A

operator

can

talk/listen

to

stations

on

Channel

A

and

stations

on

Channel

B,

but

Channel

A

stations

cannot

talk/listen

to

Channel

B

stations--

unless

a

Party

Line

system

has

been

set

up

via

the

Main

Station).

Sidetone

Adi

The

sidetone

adjustment,

which

is

controlled

with

the

blade

of

a

small

screwdriver,

allows

the

RM-120A

operator

to

add

back

a

fixed

level

of

his/her

voice

in

the

speaker

or

headset,

regardless

of

which

channels

are

selected.

When

using

the

gooseneck

and

speaker

simultaneously,

this

control

should

be

turned

all

the

way

down

to

further

reduce

the

possibility

of

feedback.

Internal

Trimpots

(schematic

reference,

P5

and

P6):

One

sidetone

null

control

per

channel;

you

need

only

adjust

the

sidetone

once

at

the

time

of

installation

(if

at

all),

even

if

other

stations

subsequently

join

or

leave

the

intercom

system.

Adjusting

the

sidetone

does

not

affect

the

level

of

incoming

or

outgoing

signals.

(continued)

4

At the

factory,

Clear-Com

sets

the

internal

sidetone

null

to

the

best

overall

null

with

500

feet

of

cable.

If

the

sidetone

is

not

nulled

enough, feedback

may

occur

between

the

speaker

and

the

mic.

To

adjust

the

internal

sidetone

null:

1)

remove

top

cover

of

unit

2)

plug

in

headset

and

turn on

mic

(or

activate

gooseneck

mic)

3)

turn

up

Headset

Volume

4)

talk

into

mic

while

slowly

turning

sidetone

adjustment

clockwise.

Find

the

null

point

where

you

can

barely hear

yourself.

This

is

the

proper

setting

for

minimum

feedback

when

using

both

the

speaker

and

a

mic.

Adjust individually

for

each channel.

Program

Volume

Speaker

Volume

Headset

Volume

These

knobs adjust

listen-levels

of

the

auxiliary program

and

overall

intercom

activity,

as

heard

in the

speaker

and

headphones.

Stage

Announce

This

push-button

activates

the

feature

designed

for

paging

appli-

cations.

The

RM-120A

provides a balanced,

line-level

output

signal

to

a

1/4" phone

jack

on

its

rear panel.

The

Stage

Announce

button

acti-

vates

this

output,

giving

the

operator

access (via

headset

or

gooseneck

mic)

to

the

external

speaker/amp

system.

Pressing

Stage

Announce

also

mutes

the

operator's voice

to

the

intercom

channels.

Vic

On/Off/(On)

This

3-position

toggle

switch

turns

the

mic on

or

off

in

your

carbon)

and

dynamic

headse

or

the

gooseneck

iic.

With-the-switch

set

to

the

top

"on"

position,

the

mic

stays

on.

When

in

the

middle

position,

the

mic

is

off. The

bottom

position

"(on)"

is a momentary

setting.

PROGRAM

INPUT

3-pin

female

XLR

connector;

pin-out assignment

is:
Pin 1--ground
Pin

2--input

Pin

3--input

The

auxiliary

program

input

is

on

the

RM-120A

rear

panel.

It

accepts

a

balanced,

line-level

input (input

impedance

is

10k

ohms

bridging;

a

0

dBv nominal

signal

drives

the

headset

to

full

output).

The

RM-120A

operator

can

monitor program

along

with intercom

activity

in

the

head-

set/speaker. A split-feed option,

set

up

at

the

Clear-Com

factory,

separates

the

intercom

and

program

signals

for

use

with a binaural

(6-

pin, stereo)

dynamic

headset.

STAGE

ANNOUNCE

OUTPUT

1/4"

phone

jack;

3-circuit (ring/tip/sleeve);

600

ohms

output impedance.

EXTERNAL

SPEAKER

OUTPUT

1/4"

phone

jack;

2-circuit (internally-switched;

ring/tip);

discon-

nects

internal

speaker;

output

for

speaker

with

impedance

of 8 ohms

or

more (preferably

16

ohms).

5

V.

RN-120A

SPECIFICATIONS

AMPLIFIER

DESIGN

Solid-state,

integrated

circuit

amplifiers

which

include

a

mic

pre-amp

with

limiter,

headset

power

amp,

speaker

power

amp,

and

signalling

circuitry.

Current-limited

with

short-circuit

and

reverse

polarity

protection.

MIC

PRE-AMPLIFIER

GENERAL

SPECS

Freq.

Response:

250-12k

Hz,

with

Line

Level:

OdBv

max,

-18dBv

nom.

mic

limiter;

contoured

Sidetone

Adj:

35

dB

null

to

full

on

to

enhance

intelligibility

Signal

Voltage:

l1VDC

on

audio

line

Mic

Input

Impedance:

lk

ohms

Call

Light

Sensitivity:

4

volts

Mic

Preamp

Gain:

+37

dB

Signal-to-Noise:

68

dB

Max

Input

Before

Clipping:

-10

dBv*

Equivalent

Input

Noise:

-118

dB

Mic

Limiter

Range:

25

dB

Station

Bridging

Impedance:

>12k

ohm (200-10k

Hz)

Power Requirements:

25

mA quiescent

HEADSET/SPEAKER

AMPLIFIER

100

mA

signal,

100

mA

avg.

talk

Freq.

Response:

100-18k

Hz,

12

dB

200

mA

short-circuit

Load

Impedance

Range:

300-2000

ohms

Voltage

Range:

12-32V,

28V

nominal

(dynamic

headset)

Dimensions:

1.75"

x

19"

x

6.5"

deep

Output

Level:

+18

dBm,

26v

p-p

44

mm

x

483

mm x 165

mm

@

200

ohms

CONNECTORS

Headset

Level:

+110

dB

SPL

Dynamic

Headset:

4-pin

XLR,

male

(with

standard

Clear-Com

headset)

Carbon

Headset:

1/4"

phone

jack

Headset

Distortion:

0.2%

THD

@

lkHz

Line:

(4)

3-pin

XLR

Headphone

Amp

Gain:

+37

dB

Channel

A--i

male,

1

female

Speaker-Type:

16

ohm,

3"x

1.5"

oval

Channel

B--i

male,

1

female

Spkr.

Amp

Output:

2.5w

into

16

ohms

Program

Input:

3-pin

XLR,

female

Speaker

Level:

+98

dB

SPL

@

3

feet

Ext. Speaker:

1/4"

phone

jack

(disconnects

internal speaker)

*

0

dBv

is

referenced

to

0.775

volts

EMS

7

VI.

RK-120A

PARTS

LISTING

Part

#

Description

Qty.

Schematic

Reference

ID

210002

Conn,

intercom/prgm,

D3F

3

210003

Conn,

intercom,

D3M

2

210013

Conn.,

headset,

D4M

1

210050

Conn.,

1/4"

phone

jack

2

J1,

stage

announce

210055

Conn.,

1/4"

jack

w/switch

1

ext.

speaker

240015

Knob,

black,

1/2"

3

P1,

P2,

P3

240017

Handle,

chrome

2

250128

RM+-120A

rear

panel

1

250224

RM-120A

front

panel

1

250073

Chassis

mainframe,

1.75"

1

250152

Chassis

top cover

1

250163

Speaker

screen

1

390013

Lamp

lens,

amber

2

L1,

L2

(390012

Bulb,

28v)

500095

Speaker,

16

ohm,

oval

1

510012

Switch,

momentary

pushbutton

2

H5

(call)

640028

Hole

plug,

3/4"

1

(without

gooseneck)

710054

Gooseneck

Mic

1

(optional)

710158

RM-120A

electronics

assy.

1

810031

RM-120A

instruction

manual

I

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