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The Latitude™ D620 ships with a new wireless
feature called the wireless on/off catcher switch. It
is located on the left side of the system right next
to the infrared port. When used in combination
with the Dell™ QuickSet utilities, this switch
enables or disables the wireless LAN and
Bluetooth® cards in the system, or it searches for
all wireless networks in range.
To scan for a Wi-Fi® wireless LAN, slide and hold
the switch in the momentary position for a few
seconds. The Wi-Fi catcher network locator
functions whether the computer is turned on or
off, in Hibernate mode, or in Standby mode, as
long as the switch is configured through QuickSet
or the BIOS to control Wi-Fi network connections.
Because the Wi-Fi catcher network locator is
disabled and not configured for use when the
computer is shipped, it must be enabled and
configured through the Dell QuickSet utilities to
control Wi-Fi network connections.
Wireless Sniffer Switch LED Settings
The LED on the wireless catcher switch functions even if the system is off. You can activate the switch and have it scan for
networks without going through a complete boot process. The switch can be set to detect for only certain wireless signals,
such as WLAN only, WWAN only, Bluetooth only, or any combination of these. This setting is in the BIOS under the
Wireless section.
The LED indicates the presence of a network as follows:
Flashing green — The system is searching for a signal.
Green — The system has detected a wireless signal and has good strength.
Yellow — The system has detected a wireless signal, but its strength is moderate to weak.
Red — The system failed to detect a wireless signal, or the wireless signal is extremely weak.
In addition to the wireless functionality, you can use the wireless catcher switch to determine a no-POST situation if there is
a problem with the power button. Here are two scenarios:
Scenario 1: A customer activates the wireless catcher switch with the system off. He gets the usual wireless activity
indicator (as described above), which indicates the system is getting power, but there may be a problem with either
the power button (more likely) or the system board (less likely). A keyboard would be sent first (since the power
button is located on the keyboard). If this does not correct the problem, then a system board is dispatched.
Scenario 2: A customer activates the wireless catcher switch with the system off. He gets a flashing no-POST code
on the diagnostic LEDs. If pressing the power button does not provide the same result, then you must replace the
keyboard for a faulty power button, and the system has other problems.
Wireless Card Offerings
With the growing emergence of cellular wireless technology, demand has grown for not only wireless LAN (local area
network) cards, but also wireless WAN (wide area network) cards.
WLAN Technology
Wireless LAN technology has been around for some time, and you should be familiar with the three WLAN standards: a, b,
and g. Coming later in 2006 is a new standard, presently called the Pre-n standard. When officially ratified, it will be referred
to as the n standard. The Latitude D620 is equipped to handle Pre-n cards once they become available.
The following WLAN cards are offered with this system:
Dell™ Wireless 1390 b/g WLAN Mini Card
Dell Wireless 1390 b/g WLAN ExpressCard&Trade; (post RTS)
Dell Wireless 1490 a/b/g WLAN Mini Card
Intel® PRO/Wireless 3945 WLAN Mini Card
WWAN Technology
Different types of WWAN cards use different technologies to make a broadband connection. Each broadband (cellular)
provider determines which technology it uses to access its WAN signal. The two most prevalent technologies are explained
below.
HSDPA — High-speed downlink packet access. HSDPA works by moving important processing functions closer to
the air interface, allowing scheduling priority to take account of channel quality and terminal capabilities. HSDPA also
adds a channel-sharing mechanism that allows several users to share the high-speed air interface channel and other
technological advances, such as adaptive modulation and coding, quadrature amplitude modulation, and channel
quality feedback. These enhancements allow HSDPA to roughly double the total throughput capacity of a network.
CDMA — Code division multiple access. A spread spectrum technology, CDMA allows many users to occupy the
same time and frequency allocations in a given band or space. As its name implies, CDMA assigns unique codes to
Wireless Technology
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22/02/2010
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