Intel ESM-2740, User Manual

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ESM-2740/2743
40 ESM-2740/2743 User’s Manual
2.4.9 Signal Description – ETX Connector X4 (ETXD)
2.4.9.1 Ethernet Signals
Signal Signal Description
TXD#, TXD
Ethernet Transmit Differential Pair. These pins transmit the serial bit stream on the
Unshielded Twisted Pair (UTP) cable. The current-driven differential driver can be
two-level (10BASE-T) or three-level (100BASE-TX) signals depending on the
mode of operation. These signals interface to the Ethernet cable through an
isolation transformer.
RXD#, RXD
Ethernet Receive Differential Pair. These pins receive the serial bit stream from the
isolation transformer. The bit stream can be transmitted in either two-level
(10BASE-T) or three-level (100BASE-TX) signals depending on the mode of
operation. These signals interface to the Ethernet cable through an isolation
transformer.
ACTLED
The Activity LED pin indicates either transmitted or received data activity on the
Ethernet port.
This pin is asserted low when activity is detected. It can sink 5mA to ground
through an external LED and a limiting resistor to a 3.3V source.
LILED
The Link Integrity LED pin indicates link integrity. This pin is asserted low when the
link is valid. It can sink 5mA to ground through an external LED and a limiting
resistor to a 3.3V source.
SPEEDLED
The Speed LED pin indicates high speed operation. This LED is not supported by
ESM-2740/2743.
This pin is asserted low when a 100Mbps link is detected, and is not asserted for a
10Mbps link. It can sink 5mA to ground through an external LED and a limiting
resistor to a 3.3V source.