KSZ8841_11 Datasheet, PDF (30/105 Pages) Micrel Semiconductor – Single-Port Ethernet MAC Controller with Non-PCI Interface

Micrel, Inc.
The IEEE 802.3u standard MDI and MDI-X definitions are:
KSZ8841-16/32 MQL/MVL/MBL
MDI
RJ45 Pins Signals
1
TD+
2
TD-
3
RD+
6
RD-
MDI-X
RJ45 Pins Signals
1
RD+
2
RD-
3
TD+
6
TD-
Table 1. MDI/MDI-X Pin Definitions
Straight Cable
A straight cable connects an MDI device to an MDI-X device or an MDI-X device to an MDI device. The following diagram
shows a typical straight cable connection between a network interface card (NIC) and a chip (MDI), or hub (MDI-X).
10/10 0 E the rnet
M e dia D e p en d e n t In te rfac
e
1
T r a n s i t Pma ir
2
3
4
R ec iv eP aeir
5
6
7
8
M od ular C onnec or t
(R J 4 5 )-
N IC
S tr a ig h t
C ab le
1 0 /10 0 E th e rn e t
M e d ia D ep e n d en t In te rfa c e
1
R e c iv eP aeir
2
3
4
T r a n s it Pma ir
5
6
7
8
M o du la r C o nn e c o r t
(R J 4 5 )-
HUB
(R e p e ate r o r S w itc ) h
Figure 7. Typical Straight Cable Connection
Crossover Cable
A crossover cable connects an MDI device to another MDI device, or an MDI-X device to another MDI-X device. The
following diagram shows a typical crossover cable connection between two chips or hubs (two MDI-X devices).
10/100 Ethernet
Media Dependent Interface
10/100 Ethernet
Media Dependent Interface
1
Receive Pair
2
3
4
Transmit Pair
5
6
7
8
Crossover
Cable
1
Receive Pair
2
3
4
Transmit Pair
5
6
7
8
Modular Connector (RJ-45)
HUB
(Repeater or Switch)
Modular Connector (RJ-45)
HUB
(Repeater or Switch)
Figure 8. Typical Crossover Cable Connection
October 2007
30
M9999-102207-1.6