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Page 304 of 504 Digital telephones line engineering
553-3001-367 Standard 3.00 August 2005
Procedure 53
Calculating expected pulse loss
1 Collect loop makeup data between the line card and the terminal. For
each cable section, the data required is:
• cable type (PIC or pulp)
• gauge
• length
• type of plant construction (underground, aerial, or in-building)
2 Calculate individual cable section losses by using the figures in Table 42
on page 305 through Table 44 on page 306, and the following equation:
CSLi = SLi x Li
• CSLi = cable section loss for section i
• SLi = section length of section i
• Li = loss per unit length for section i
3 Correct individual cable section losses for maximum cable temperature
by using the following equation:
TCLi = CSLi x TCFi
• TCLi = temperature corrected loss for section i
• TCFi = temperature correction factor for section i
Correction factors:
• aerial cable TCF = 1.1
• underground cable TCF = 1.04
• in-building cable TCF = 1
4 Determine junction loss (see Figure 49).
Note: Junction loss due to gauge discontinuity of outside plant cables
and D inside wire varies between 0.03 dB and 0.07 dB and can be
ignored. However, AMP 25-pair under-carpet wiring has a characteristic
impedance of 40 ohm at 256 kHz, and its junction loss is approximately
2 dB. This must be included in the calculation.
5 Calculate the expected pulse loss (EPL) by finding the sum of the items.