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Chapter 3
Installing the Router
Connecting to the Console and Auxiliary Ports
Note
The RJ-45 and MII receptacles on the GRP represent two physical connection
options for one Ethernet interface; you can use either the MDI RJ-45 connection
or the MII connection, but not both simultaneously. The transmission speed of the
Ethernet port is set through an auto-sensing scheme on the GRP.
The speed is determined by the network to which the Ethernet interface is
connected, and is not user-configurable. Moreover, even at the auto-sensed data
transmission rate of 100 Mbps, the Ethernet port provides maximum usable
bandwidth of less than 100 Mbps. Expect a maximum usable bandwidth of
approximately 20 Mbps when using either the MII or RJ-45 connection.
The Ethernet port can use either unshielded twisted-pair or screened twisted-pair
cable. In sites where extremely high immunity to noise is required, screened
twisted-pair cable is recommended. Figure 3-12 shows the layout of the Ethernet
MII receptacle on the GRP.
Figure 3-12
Ethernet MII Receptacle
H6538
Pin 1
Jackscrew
Pin 21
Table 3-5 lists the signal-to-pin correspondence for the Ethernet MII connector.
Table 3-5
Ethernet MII Pin Configuration
Pin1
In
Out
Input/Output
Description
Code
14 to17
–
Yes
–
Transmit Data
TxD
12
Yes
–
–
Transmit Clock
Tx_CLK2
11
–
Yes
–
Transmit Error
Tx_ER
13
–
Yes
–
Transmit Enable
Tx_EN
3
–
Yes
–
MII Data Clock
MDC
4 to 7
Yes
–
–
Receive Data
RxD
Cisco 12006 and Cisco 12406 Router Installation and Configuration Guide
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