Emerson ROC827 instruction manual Ethernet Signal LEDs, Signal Function

ROC827 Instruction Manual

You can link Ethernet networks together to form extended networks using bridges and routers.

Table 5-6. Ethernet Signal LEDs

Signal	Function
RX	Lit when currently receiving.
TX	Lit when currently transmitting.
COL	Lit when Ethernet Packet Collision detected.
LNK	Lit when Ethernet has linked.

Use a rugged industrial temperature HUB when connecting Ethernet wiring in an environment that requires it.

The IEEE 802.3 10BASE-T standard requires that 10BASE-T transceivers be able to transmit over a link using voice grade twisted-pair telephone wiring that meets EIA/TIA Category four wire specifications. Generally, links up to 100 meters (328 feet) long can be achieved for unshielded twisted-pair cable.

For each connector or patch panel in the link, subtract 12 meters (39.4 feet) from the 100-meter limit. This allows for links of up to 88 meters (288 feet) using standard 24 AWG UTP (Unshielded Twisted-Pair) wire and two patch panels within the link. Higher quality, low attenuation cables may be required when using links greater than 88 meters.

The maximum insertion loss allowed for a 10BASE-T link is 11.5 dB at all frequencies between 5.0 and 10.0 MHz. This includes the attenuation of the cables, connectors, patch panels, and reflection losses due to impedance mismatches to the link segment.

Intersymbol interference and reflections can cause jitter in the bit cell timing, resulting in data errors. A 10BASE-T link must not generate more than 5.0 nanoseconds of jitter. If your cable meets the impedance requirements for a 10BASE-T link, jitter should not be a concern.

The maximum propagation delay of a 10BASE-T link segment must not exceed 1000 nanoseconds.

Crosstalk is caused by signal coupling between the different cable pairs contained within a multi-pair cable bundle. 10BASE-T transceivers are designed so that you do not need to be concerned about cable crosstalk, provided the cable meets all other requirements.

Noise can be caused by crosstalk of externally induced impulses. Impulse noise may cause data errors if the impulses occur at very specific times during data transmission. Generally, do not be concerned about noise. If you suspect noise related data errors, it may be necessary to either reroute the cable or eliminate the source of the impulse noise.

Multi-pair, PVC 24 AWG telephone cables have an attenuation of approximately 8 to 10 dB/100 m at 200°C (392°F). The attenuation of PVC insulted cable varies significantly with temperature. At temperatures

Issued Mar-06 Communications 5-8