C-26 Sun Ultra 60 Service Manual • August 2001
C.1.12.2 External Transceivers
The following external transceivers are connected through the MII port:
■6211Micro 100BASE-FX FastEthernet transceiver
■CT4-1030 100BASE-T4 transceiver
■CFX-107X 100BASE-FX transceiver
■XF467A MII-to-AUI transceiver
C.1.12.3 External Cables
The MII port supports a 0.5-meter long, 40-conductor,20 signal-ground, STP cable.
The single-ended impedance of the cable is 68 ohms (+/-10%). The propagation
delay for each twisted-pair,measured from the MII connector to the PHY, does not
exceed 2.5 nanoseconds.
The RJ45 Ethernet port supports a Category 5, UTP cable for the 100BASE-T,and a
Category 3, 4, or 5 UTP cable for the 10BASE-T operation.
Note – The maximum cable segment lengths for the 100BASE-TX and
10BASE-TX are 100 meters and 1000 meters, respectively.
C.1.12.4 Connectors
A 40-pin connector is used for the MII connector.A standard 8-pin RJ45 connector
with a shield is used for the AUI connector.
C.1.12.5 MII Power
A regulated5-Vdc (+/- 5%) voltage is supplied to the PHY IC over the load range of
from 0 to 750 mA. A 2-amp overcurrent protectioncircuit is provided by a polymer-
based resettable fuse to the MII supply voltage.
MII-to-AUI connection to a 10-Mbps medium attachment unit requires a
supplemental power source to meet the AUI power supply requirements. The MII-
AUI converter provides the necessary supplemental power.
C.1.12.6 MII Port Timing
MII port timing encompasses two configurations involving the use of either an on-
board transceiver or external transceivers. For either transceiver configuration, the
MII port timing is the same because MII operates with a 40-nanosecond cycle time.