DL8000 Preset Instruction Manual
Revised February-2016
Modules
3-37
MAC mechanism is based on Carrier Sense Multiple Access with
Collision Detection (CSMA/CD). If two stations begin to transmit a
packet at the same instant, the stations stop transmitting (Collision
Detection). Transmission is rescheduled at a random time interval to
avoid the collision.
Link Ethernet networks together to form extended networks using
bridges and routers.
Table 3-11
maps the LEDs to functions.
Table 3-11. 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 meter (328 feet) long are
achievable 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