AM79C985 Advanced Micro Devices, AM79C985 Datasheet - Page 31

• Manufacturer Part Number: AM79C985
• Description: enhanced Integrated Multiport Repeater Plus (eIMR+)
• Manufacturer: Advanced Micro Devices

SYSTEMS APPLICATIONS
eIMR+ to TP Port Connection
The eIMR+ device provides a system solution
to designing non-managed multiport repeaters. The
eIMR+ device connects directly to AC coupling mod-
ules for a 10BASE-T hub. Figure 9 shows the simpli-
fied connection.
Twisted Pair Transmitters
TXD signals need to be properly terminated to meet the
electrical requirement for 10BASE-T transmitters.
Proper termination is shown in Figure 10 which consists
TXD+
TXD-
110
RST
CLK
Figure 9. Simplified 10BASE-T Connection
eIMR+
TXD0+
TXD1+
TXD2+
TXD3+
TXD0–
RXD0+
RXD0–
TXD1–
RXD1+
RXD1–
TXD2–
RXD2+
RXD2–
TXD3–
RXD3+
RXD3–
Figure 10. TXD Termination
P R E L I M I N A R Y
110
100
110
100
110
100
110
100
Am79C985
1:1
1:1
1:1
1:1
1:1
1:1
1:1
1:1
1:1
of a 110-
twisted-pair cable that meets IEEE 802.3, Section 14.4
specifications. The cable is terminated at the opposite
end by 100 .
Twisted Pair Receivers
RXD signals need to be properly terminated to meet
the electrical requirements for 10BASE-T receivers.
Proper termination is shown in Figure 11. Note that the
receivers do not require external filter modules.
TP Connector
TP Connector
TP Connector
TP Connector
resistor and a 1:1 transformer. The load is a
Twisted Pair
100
20650A-13
20651B-14
20651B-15
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