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Saturated optical power, Copper transceiver modules, Data rate – H3C Technologies H3C S12500 Series Switches User Manual

Page 13: Transmission distance, Connector

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Saturated optical power

Saturated optical power (also known as optical saturation) is the maximum receive power at a given data

rate and bit error rate range (10

-10

to 10

-12

), in dBm.

Saturated photocurrent occurs if a fiber probe is irradiated by intensive light. When this occurs, it takes

the probe some time to recover. In this case, the receiving sensitivity worsens and the received signals

may be decided incorrectly, causing bit errors. This will probably damage the receiving probe. Therefore,

when you perform operations, try to maintain a normal saturated optical power level.

Copper transceiver modules

Copper transceiver modules are used for transmitting signals over Category-5 unshielded twisted pair

(UTP). UTP transmission cover shorter distances than optical transmission and can be used in small-sized

networks only.
H3C devices support only SFP copper transceiver modules.

Data rate

The data rates of copper transceiver modules supported by H3C devices are 1250 Mbps.

Transmission distance

Through UTP cables, electrical signals can be transmitted over a distance of 100 m (328.08 ft) only. This
is because electrical signals attenuate during transmission through the UTP cables.
Attenuation refers to the dissipation of the power of a transmitted signal as it travels over a cable.

Attenuation occurs because signal transmission suffers certain resistance from the cable, which weakens

the electrical signals as they travel over the cable. When signals are transmitted over a very long
distance, signal strength decreases very significantly, causing the signal-to-noise ratio to drop below the

accepted level. This makes it impossible to distinguish between signals and noise, resulting in decision

errors.
When signals are to be transmitted over a short distance, use copper transceiver modules only.

Connector

RJ-45 (Registered Jack-45) twisted pair connectors are used as the connectors for copper transceiver

modules.

Figure 6

shows the appearance of an RJ-45 connector.

Figure 6 RJ-45 connector

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