AN2456

Telecom disturbances

3/15

1

Telecom disturbances

Figure 2 shows the different disturbances that may appear on the telecom line. Among

these, lightning and power crossing are the main considerations for wireline applications.

These disturbances are well defined in the country standards.

Figure 2.

Line disturbance causes

As the purpose of this application note is to illustrate the protection topology needed for

short line SLICs located in RT in customer premises in the US, the standard to be

considered for lightning and power crossing tests is the Telcordia GR1089 Intrabuilding

(equipment port type 4).

The Telcordia GR1089 specifies two acceptance criteria:

●

First level: the equipment shall continue to operate properly after the test.

●

Second level: the equipment may be damaged, but should not become a fire or

electrical hazard.

For intrabuilding equipment, however, only first level acceptance criterion need to be

satisfied for lightning tests.

Table 1 and Table 2 give the list of lightning and power crossing tests in the Telcordia

GR1089 intrabuilding standard for equipment port type 4.

Table 1.

Telecordia GR1089 intrabuilding lightning tests

Surge

Peak voltage

(V)

Peak current

(A)

Voltage and

current

waveforms

(µs)

Repetitions of

each polarity

Test

1.

M: metallic; L: longitudinal

1

±800

100

2/10

1

M (on tip and ring)

2

±1500

100

2/10

1

L

Remote

Terminal

Central office

Short

line

SLIC

Subscriber

Location

Atmospheric effects (Lightning)

50/60Hz mains disturbances

Electrostatic discharges

POTS

Protection

Protection