Toshiba STRATA DK14 Installation And Maintenance Manual page 629

Flowchart 14-4 CO Line Dial Tone Faults
START
1. Check CO line wiring per Chapter 10.
2. Test central office line using a
standard telephone or butt set at the
TELCO block.
Repair as necessary.
4-1
Change the DK14 or DK40i Base KSU or test
the DK424 or DK424i common control PCB
per the Fault Isolation section and initialize the
Strata DK I&M 6/00
Is the fault Yes
cleared?
No
4-2
Are all
faulty CO lines
on a replaceable PCB
(not including KSU
Yes
motherboard)?
No
4-7
Are the
faulty CO lines
Yes
only in the DK40i
Expansion KSU or one
DK424/DK424i
Cabinet?
No
4-10
system (Prog. 91-9 and 03).
Retest.
Is the
No
fault
cleared?
Yes
Go to
4-5
END
Change the PCB
4-3
and retest.
4-4
Is the
No
fault
cleared?
Yes
4-5
Replace the defective
unit and return it to the
repair center.
END
Change the expansion
4-9
unit and retest.
4-6
Is the
fault
cleared?
No
Call your technical
support group.
Fault Finding
Fault Isolation Flowcharts
Replaceable CO Line
PCBs:
DK14 QCDU
DK40i Base KCOU
KSU: TCOU
TDDU
TBUU
DK40i only: KCDU
DK40i RCOU
Expansion RCIU2
KSU/DK424/ REMU
DK424i: RDDU
PCOU
DK424/ REMU
DK424i only RCOS
RGLU
RBUU
Yes
Go to
4-5
1882
14-13