Type of LDCM Short range (SR) Short range (SR) Medium range
(MR)
Long range (LR)
Minimum output
power
1)
–21 dBm –13.7 dBm –3.2 dBm –1.3 dBm
Minimum receiver
sensitivity
–32.5 dBm –32.5 dBm –30 dBm –30 dBm
Optical link
budget
2)
11.5 dB 18.8 dB 26.8 dB 28.7 dB
1) Minimum output power is measured with 1 m of the selected fiber and the high power mode.
2) The optical budget includes a satisfactory margin for aging in transmitter and receiver during 20–30
years.
Table 63: Example of input data for calculating the optical budget (maximum distance)
Type of LDCM Short range (SR) Short range (SR) Medium range
(MR)
Long range (LR)
Type of fibre Multi-mode fiber
glass 50/125 μm
Multi-mode fiber
glass 62.5/125
μm
Single-mode fiber
glass 9/125 μm
Single-mode fiber
glass 9/125 μm
Modem type 1MRK0002122-
AB
1MRK0002122-
AB
1MRK002311-AA 1MRK002311-BA
Typical
attenuation in
fibre-optic cables
3 dB/km
3 dB/km 0.32 dB/km 0.21 dB/km
Attenuation/
Contact
1.5 dB/ST 1.5 dB/ST 0.3 dB/FC/PC 0.3 dB/FC/PC
Factory splice
attenuation
0.5 dB/splice
0.3 splices/km
0.5 dB/splice
0.1 splices/km
0.08 dB/splice
0.1 splices/km
0.08 dB/splice
0.1 splices/km
Repair splices 0.25 dB/splice
0.1 splices/km
0.25 dB/splice
0.1 splices/km
0.1 dB/splice
0.05 splices/km
0.1 dB/splice
0.05 splices/km
Fiber margin for
aging
0.1 dB/km 0.1 dB/km 0.01 dB/km 0.01 dB/km
Table 64: Example of calculating the optical budget (maximum distance)
Type of LDCM
Short range (SR) Short range (SR) Medium range
(MR)
Long range (LR)
Type of fibre Multi-mode fiber
glass 50/125 μm
Multi-mode fiber
glass 62.5/125
μm
Single-mode fiber
glass 9/125 μm
Single-mode fiber
glass 9/125 μm
Modem type 1MRK0002122-
AB
1MRK0002122-
AB
1MRK002311-AA 1MRK002311-BA
Maximum
distance
2 km 3 km 80 km 120 km
Attenuation in
fibre-optic cables
6 dB 9 dB 25.6 dB 25.2 dB
2 contacts 2 dB 3 dB 0.6 dB 0.6 dB
Table continues on next page
Section 22 1MRK 506 369-UEN B
Remote communication
848 Line distance protection REL670 2.2 IEC
Application manual
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