Watch Standing

switches for the equipment associated with the fuse to

provided with automatic fault detection, fault

the down (out of service) position.

reporting, and fault isolation aids.

If the failed fuse is associated with the ringing

The system's alarm panel displays failure alarms,

halts the processor, overrides an emergency transfer

generator or interrupter board, set the appropriate

condition, and initiates built-in processor diagnostic

transfer switch to the down position and replace the

fuse.

routines. Two alarms are generated by the system, a

major alarm and a minor alarm. A major alarm usually

ATB ALARM

indicates a failure that removes a large number of

stations from service. A minor alarm is always

A lighted automatic transfer bus (ATB) alarm

indicated by a fault indicator light that helps isolate

lamp indicates that all available links are being used.

the fault. Both alarms have relay-operated circuits to

The only action that can be taken to satisfy this alarm

a remote alarm panel.

is to place any links that may be manually switched

The maintenance and administration panel

out of service, for test purposes, back into service.

executes the maintenance routines and displays the

results. It also is used to modify the system's

OFF HOOK ALARM

parameters and to monitor telephone traffic.

A lighted OFF HOOK alarm lamp indicates that

at least one link circuit is being held by an off-hook

WATCH STANDING

condition for longer than 30 seconds with no valid

One of your duties as the IC room watch stander

connection being made. Check the links; the monitor

will be to isolate and clear automatic telephone

lamp on the link serving the off-hook line will be

flashing.

switchboard alarms. When a malfunction occurs

during normal operation of the telephone switchboard,

You can determine the number of the line causing

a remote audible alarm will sound. When this happens,

the off-hook alarm by inspecting the crossbar switch

you should open cabinet 2 of the switchboard and

contacts, the select level contacts, and the originating

silence the audible alarm by momentarily operating

hold magnet. Find the contacts being held closed by

the ALM RESET switch located on the switch and fuse

the originating hold magnet corresponding to the link.

panel to the up position. After you silence the audible

The number of the line causing the alarm can be

alarm, check the alarm lamps (POWER, FUSE, ATB,

determined by observing the closed unit contacts and

OFF HOOK, RINGER) on the switch and fuse panel.

level selecting contacts. First move the switch for that

The source of the malfunction will be indicated by one

line to the down (out of service) position. Then move

or more of the lamps being lit. The procedures for

the busy switch for the link in trouble to the down

isolating and clearing the alarm condition(s) will be

position. This clears the link, and the busy switch may

discussed in the following paragraphs.

be returned to the up position.

POWER ALARM

RINGER ALARM

A lighted POWER alarm lamp indicates a loss of

A lighted RINGER alarm lamp indicates that the

primary ac power from the main IC switchboard.

on-line ringing generator has failed. Set the RG1

Check the circuit J switch on the main IC switchboard

20HZ/RG2 switch located on the switch and fuse

for a blown fuse. If a fuse has blown, replace it. If the

panel in cabinet 2 to the appropriate position to select

new fuse blows, notify your supervisor.

the standby ringing generator.

FUSE ALARM

MAINTENANCE

A lighted FUSE alarm lamp indicates failure of

one of the fuses on the switch and fuse panel in either

As an IC Electrician third class, you will be

cabinet 1 or 2. Check both cabinets and look for a

required to perform routine preventive maintenance

flagged fuse. When the open fuse is located, inspect

on the switchboard. Since corrective maintenance

the associated equipment and circuitry for broken

should be performed by a qualified technician

wires or burn marks. If no obvious trouble is found,

specifically trained on this system, only preventive

replace the fuse. If the new fuse fails, set the switch or

maintenance will be discussed.

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