MRC MCX-5000 Series, Manual

Page: 22 / 220

MARINE RADIO CO.,LTD.
주
/
선박무선
Subject : Auto Exchanger Page : (21 / 46)
Date : 2010.10.13 Doc. : MCX-5000S_ENG_R1
(QAS-ADD-008/1/10.10.13) manual\pabx\mcx-5000S\MCX-5000S_eng.doc
( MARINE RADIO CO., LTD.) MRC
3.6 I.S. Type Telephone(LC-213K,L,M)
This telephone system is designed for intrinsically safe construction and proper ignition grade(IIC T6) so
that it can be communicated in hazardous area where gas can be exploded.
The intrinsically safe construction does not ignite explosive gas or dust when the heat is caused by short
circuit, broken line and ground. Also, it is especially designed for ship to prevent water, humidity and
insects. This system, the telephone set and calling unit, has switch, terminal and replay. In calling, it uses
an air horn in hazardous area, and uses the buzzer and bell in safety area.
The telephone set adapts the low noise OP-AMP, so it improves call tone and side tone. Moreover, it
largely reduces noise incoming through a telephone transmitter, by using the circuit whose
CMRR(Common Mode Rejection Ratio)is high.
The power is supplied to "JB Box". The current and voltage are limited for explosion-proof architecture.
As shown in figure below, the Intrinsic Safety system is largely divided into two groups; One is telephone
set(Portable) and another is calling unit(Relay and terminal).