Station Cable Continuity Check; Voltmeter Test; Ohmmeter Test; Cable Installation - Toshiba Strata DK 280 Installation Manual

12.6 Station Cable Continuity Check
12.6.1 Voltmeter Test
Use a voltmeter to check cable continuity between the
DK280 KSU, digital or electronic telephone and the
DSS or attendant console. Make tests at the modular
block. Refer to Tables 12-1 and 12-3 and follow these
steps:
1.
,
2.
3.
4.
5.
6.
Disconnect attendant console from the RJ11 wall
jack; with RATU installed, measure each of the
two attendant console pairs at the attendant
console wall jack. The attendant console loop
voltage must be within (k43.2 - G2.6 VDC).
Refer to Chapter 7-Wiring Diagrams for
appropriate MDF wiring diagrams.
Disconnect the digital or electronic telephone,
DSS console, PDIU-DS, HDCB, or DDCB.
Using a DC voltmeter, measure between the wires
of the two pairs to verify the readings shown in
Table 12-1 for electronic telephone ports (PEKU
or PESU). Refer to Table 12-3 for digital telephone
ports. The reading will be a plus or minus
depending on meter lead placement.
An improper reading indicates an open, crossed or
shorted wire.
For the MDF-to-telephone (digital or electronic)
cable, use an ohmmeter to make a more precise
check.
12.6.2 Ohmmeter Test
The continuity of the cable run between the KSU and
digital or electronic telephone is checked with an
ohmmeter as follows:
1. Disconnect the attendant console, DSS console,
electronic or digital telephone.
2. At the MDF, remove the bridging clips.
3. At the MDF, place shorting jumper wires between
the T and R of pair #l (green-red), the T and R of
pair #2 (black-yellow) and the T and R of OCA pair
#3 (blue-white), for PEKU/PESU only. (For MDF
pin numbers, see Chapter 7-Wiring Diagrams.)
4. At the modular block, measure the resistance
between all wire combinations. The proper
readings are shown in Table 12-2 for electronic
telephones and HDSSs, and Table 12-4 for
attendant console, digital telephones, DDSSs and
DDCBs.
12.6.3 Cable Installation
If cable voltmeter and ohmmeter tests are within limits,
digital telephones, attendant consoles, DDCBs, or
DDSS consoles may not operate because of the
following:
1.
2.
3.
4.
Cable runs for the above digital devices must be
free of cable splits (single or double). Test for and
eliminate all cable splits.
Cable bridge taps - Digital telephones will not
operate if cable runs contain any type (short or
long) of cable bridge. Test for and eliminate all
cable bridges.
When installing the station cable, do not run
parallel to and within 3 feet of'an AC power line.
AC power lines should be crossed at right (90")
angles only. In particular, avoid running station
wire pairs near devices that generate electrical
noise, such as neon or fluorescent light fixtures.
Check Table 7-4, in Chapter 'i-wiring Diagrams.
Verify that your telephone is wired correctly (2-pair
or External power) for the options it supports
(ADM, RPCI-DI, PDIU-DI, HHEU, DVSU, etc.).
12.7 Fault Isolation Flowcharts
The following troubleshooting flowcharts are available
to aid in fault isolation. Toshiba recommends readihg
Sections 12.1 - 12.4 before proceeding
to Flowchart
12-1 to begin fault isolation.
January 1996
12-5