Main Assemblies of the System Cabinet

SHIP/SHORE FRAME PANEL (1500

switches are located in this panel. This panel is also

ASSEMBLY).-- This panel has the capability of

where a station can be wired for executive-

connecting the eight ship lines to the shore lines. It is

right-of-way or become part of a line hunt group.

used to monitor the ring and busy interrupter circuits

SELECTOR PANEL (700 ASSEMBLY).--

and to give visual indication that the attendant's

There are five selector panels, each containing three

console is energized. The panel also provides a direct

identical selector circuits. The selector circuit

audio path to the attendant's console for test purposes.

provides the means by which a telephone station can

SYSTEM POWER DISTRIBUTION PANEL

call any other station in the system. Specifically, the

(1600 ASSEMBLY).-- This assembly contains two

selector performs the basic functions of busy testing

solid-state ring generators, switches for controlling

available connectors, ringing, ring trip, extension of

ring voltages, and four major power distribution buses

the line restriction feature, and call answer.

and their associated terminal connectors.

POWER SUPPLY (800 ASSEMBLY).-- The

SYSTEM CONNECTION PANEL (1700

power supply unit uses a single-phase, full-wave

ASSEMBLY).-- Eight terminal blocks are mounted

rectifier with choke input for regulation and diode

on this panel. They are used as connection points for

surge current protection. A choke together with filter

various system functions.

capacitors provide low ripple dc power. A two-

position power selector switch is provided. Turn it to

BATTERY CHARGER (1800 ASSEMBLY).--

the 125V position if input ac power is greater than 120

The battery charger is a standard, alternating to direct

volts, If input ac power is less than 120 volts, turn it

current, solid-state unit. It can maintain a 23-, 24-, or

to the 115V position. Each switchboard contains its

25-cell battery in a fully charged condition. The output

own power supply unit.

voltage is adjustable from 48 volts to 56 volts dc at a

maximum charging rate of 6 amperes.

POWER DISTRIBUTION PANEL (900

ASSEMBLY).-- This assembly distributes dc power

In recent years, ships equipped with the MDM

to equipment in the switchboard cabinet.

system have had, via authorized SHIPALT, the 1800

assembly remotely located. A switch panel has been

Main Assemblies of the System Cabinet

installed in the 1800 assembly cavity that facilitates

individual switchboard power-down for corrective

The system cabinet consists of nine main

and preventive maintenance actions.

assemblies: 1100, 1200, and 1300 through 1900. Four

SYSTEM MONITOR PANEL (1900 ASSEM-

of these (1100, 1200, 1300, and 1500) are associated

BLY).-- The system monitor panel is integrated in the

with the operation of the attendant's console.

MDM system. It monitors and tests all finder/selectors

SHIP LINE MODULES (1100 ASSEM-

and connectors in the system. The panel contains call

BLY).-- There are eight identical ship line modules,

count indicators and all-trunks-busy indicators.

one for each ship line connected to the attendant's

Voltage monitoring and alarm locating circuits give

console.

the maintenance person a quick indication to the

SHORE LINE MODULES (1200 ASSEM-

condition of any switchboard cabinet in the system.

BLY).-- There are eight identical shore line modules,

ATTENDANT'S CONSOLE.-- The MDM

one for each shore line associated with the attendant's

200/700 installations are equipped with attendant's

console.

switching circuitry to provide for attendant-assisted

SHIP/SHORE CONTROL MODULE (1300

ship-to-shore communications. This circuitry is

mounted in the system cabinet (fig. 6-26), and consists

A S S E M B L Y ) . -- This module contains all the

of eight ship-line panels (one for each ship line) and

necessary circuitry to control the operation and

interconnection of the ship and shore lines through the

one control panel. The attendant's switching circuit is

attendant's console.

controlled from a remotely located attendant's console

(fig. 6-28).

RING/BUSY INTERRUPTER PANEL (1400

Since all of the attendant's switching equipment

A S S E M B L Y ) . -- This panel consists of tone

is mounted in the system cabinet, each console (a

interrupter circuits and a ring timing circuit. It

maximum of three per system) is used only to perform

generates ground pulses that control ring voltage and

the functions of a standard telephone with push-button

busy tone interruptions used in the selector circuitry.

6-34