Class II
Hub
100 meters TP
crossover
@ 1.11BT/meter
= 111BT
5 meters TP
crossover
@ 1.11BT/meter
= 5.55BT
= 92BT
Class II
Hub
= 92BT
100 meters TP
straight-through
@ 1.11BT/meter
= 111BT
DTE= 50BT
50.00BT
+111.00BT
+92.00BT
+5.55BT
+92.00BT
+111.00BT
50.00BT
___________
= 511.55BT
hub
3
4
5
2
hub
3
4
2
100 meters TP
straight-through
100 meters TP
cross-over
1
100 meters TP
cross-over
100 meters TP
cross-over
100 meters TP
cross-over
100 meters TP
straight-through
100 meters TP
straight-through
100 meters TP
straight-through
Link
UTP/STP
Fiber
Link
FDX
Power
100
Link
UTP/STP
Fiber
Link
FDX
Power
100
RJ-45
P
LUG
RJ-45
J
ACK
1
8
2 3 4 5 6 7
1
8
10BASE-T C
able
10
0BA
SE-TX
Cable
1
0
0B
AS
E-SX
Ca
ble
7
6
The two active pairs in a 10BASE-T or 100BASE-TX
network are pins 1 & 2 and pins 3 & 6. Use only
dedicated wire pairs (such as blue/white &
white/blue, orange/white & white/orange) for the
active pairs.
The two wires in each pair of the cable must be
twisted together for the entire length of the segment
and kept twisted to within approximately 1/2 inch of
any connector to ensure the integrity of the signal-
carrying characteristics of the unshielded wire pair.
To calculate the round trip delay in bit-times between a station (DTE)
and the Switch, find the longest path between the station and the
Switch. Calculate the round trip
delay for each cable segment
by multiplying the length of the
cable (in meters) by the delay
per meter (in bit-times (BT)).
Calculate the total round trip
delay by taking the sum of all
the cable delays plus station
(DTE) and repeater delays. If the result is less than or equal to 512 bit-
times, the path passes the test. NOTE: Installing the bridging media
converter in the network separates collision domain, so the 512-bit
rule applies separately to each 100BASE-TX or 100BASE-SX half-
duplex collision domain.
A segment is the cable connection between interfaces. A
transmission path between any two terminal devices
(including the Transition Networks’ Switch) in the same
collision domain can consist of no more than five
segments. To assign segment numbers to cable
connections, determine the network device separated
from the Switch by the greatest number of segments.
Define a segment path between that network device and
the Switch by labeling the cable connection to the Switch
“segment 1” and numbering each segment in the path to
the network device up to “segment n” (n = total number
of segments
≤
5). Verify that no segment path in the
collision domain contains more than n
≤
5 segments.
NOTE: Installing the Switch in the network separates
collision domains, so the 10BASE-T 5-Segment Rule
applies separately to each 10BASE-T collision domain.
Class I Repeater
140 BT
Class II Repeater
92 BT
Class I TX/FX Media Converter
130 BT
Class II TX/FX Media Converter
92 BT
DTE
50 BT
1 meter of CAT.5 TP cable
1.11 BT
1 meter of fiber cable
1 BT
Fast Ethernet Switch
50 BT
NOTE: Media converter is pinned as DTE device.
Crossover Cable
at RJ-45 Plug
Bridging Media Converter Network Device
RJ-45 Male . . . . . . . . . . . . .RJ-45 Male
1
(TX+)
. . . . . . . . . . . . . . . 3
2
(TX-)
. . . . . . . . . . . . . . . 6
3
(RX+)
. . . . . . . . . . . . . . 1
6
(RX-)
. . . . . . . . . . . . . . . 2
Straight-Through Cable
at RJ-45 Plug
Bridging Media Converter
Network Device
RJ-45 Male . . . . . . . . . . . . .RJ-45 Male
1
(TX+)
. . . . . . . . . . . . . . . 1
2
(TX-)
. . . . . . . . . . . . . . . 2
3
(RX+)
. . . . . . . . . . . . . . 3
6
(RX-)
. . . . . . . . . . . . . . . 6
Installing Network Cable
Use care when installing network cable to ensure that the restrictions
that apply separately to each cable type, 10BASE-T, 100BASE-TX, and
100BASE-SX (See page 11), and to each collision domain, are satisfied.
10BASE-T Half-Duplex Collision Domain
5-Segment Rule
100BASE-TX/100BASE-SX Half-Duplex Collision Domain
512-Bit Rule
Twisted-pair Copper Straight-Through /Crossover Configurations
C/E-PSW-SX-01
