Compaq 4000N - Manual (Page 125)

Technical Reference Guide
Compaq Deskpro 4000N and 4000S Personal Computers
First Edition - September 1997
5-35
5.7 ETHERNET INTERFACE
The system board integrates an Ethernet interface that supports both 10 and 100 Mbps Ethernet
communications using IEEE 802.3 (ISO 8802-3) protocol. Two connection options are available;
an RJ-45 jack for twisted-pair Ethernet (TPE) systems (10BaseT and 100BaseTX) and an AUI
connector for a direct 10BaseT connection or to a 10Base2 connection through and AUI-to-BNC
adapter. The Ethernet interface (Figure 5-9) is based on the Texas Instruments TLAN3.1
component, which operates off the PCI bus and features auto-switching between 10 and 100 Mb/s
interfaces.
Figure 5–8. Ethernet Interface Block Diagram
The RJ-45 connctor is the default port, which is the required connection if Remote Wakeup
operation or 10/100 autosensing is desired. Note also that the LED indicators are operational
only for the RJ-45 interface. The LEDs provide the following indications:
Link LED (yellow) - Indicates reception of link pulses in 10 Mbs mode, indicates scrambler lock
and valid idle code reception during 100 Mbs mode.
Active LED (green) - Indicates network activity.
The network interface controller supports Remote Wakeup using the Magic Packet method of
waking up a system unit that is powered down (the NIC logic is powered by +5 AUX, which is
active as long as the system is receiving AC line voltage). With Remote Wakeup feature enabled,
a received Magic Packet results in the PINTA- signal being asserted (low) and routed to power
control logic, which in turn activates the power supply (refer to Chapter 7, “Power and Signal
Distribution” for a discussion of the power control logic).
AUI Connector
TX/RX
RJ-45 Connector
TX/RX TX/RX
Filter
TLAN3.1
Ethernet
Controller
PCI Bus
TX/RX
+12 VDC
PINTA-
INT Cntlr.
& Power
Control
Logic
Filter
PHY
Active
(Green)
Link
(Yellow)
TX/RX,
Cntrl