Commonly used abbreviations and acronyms by IEEE 802.11 (including latest additions to 11AX)

Abbreviations and Acronyms

Abbreviations	Definations
3GPP	3rd Generation Partnership Project
40MC	forty MHz capable 802.x LAN IEEE 802-based local area networks such as IEEE Std 802.3 and IEEE Std 802.11
A-BFT	association beamforming training
A-Control	Aggregated control(#8176)
A-MPDU	aggregate MAC protocol data unit
A-MSDU	aggregate MAC service data unit
AA	authenticator address
AAA	authentication, authorization, and accounting
AAD	additional authentication data
AC	access category
ACI	access category index
ACM	admission control mandatory
ACU	admission control unit
ADDBA	add block acknowledgment
ADDTS	add traffic stream
AES	advanced encryption standard
AES-128-CMAC	advanced encryption standard (with 128-bit key) cipher-based message authentication code
AFC	automatic frequency control
AGC	automatic gain control
AID	association identifier
AIFS	arbitration interframe space
AIFSN	arbitration interframe space number
AKM	authentication and key management
AKMP	authentication and key management protocol
AMPE	authenticated mesh peering exchange
ANIPI	average noise plus interference power indicator
ANPI	average noise power indicator
ANQP	access network query protocol
ANonce	authenticator nonce
AP	access point
APSD	automatic power save delivery
ARP	Address Resolution Protocol
AS	authentication server
ASEL	antenna selection
ASN.1	Abstract Syntax Notation One
ASRA	additional step required for access
ATI	announcement transmission interval
ATIM	announcement traffic indication message
AV	audio video
AWV	antenna weight vector
Ack	acknowledgment
BA	block acknowledgment
BAR	block acknowledgment request
BC	beam combining
BCC	binary convolutional code
BCU	basic channel unit
BF	beamforming
BHI	beacon header interval
BIP	broadcast/multicast integrity protocol
BPSK	binary phase shift keying
BQR	Bandwidth query report(#4727)
BRP	beam refinement protocol
BRPIFS	beam refinement protocol interframe space
BSA	basic service area
BSR	Buffer status report(#4727)
BSRP	Buffer status report poll(#8191)
BSS	basic service set
BSSID	basic service set identifier
BT	bit time
BTI	beacon transmission interval
BU	bufferable unit
BW	bandwidth
C-MPDU	coded MPDU
C-PSDU	coded PSDU
CAP	controlled access phase
CAQ	channel availability query
CAS	Command and status(#3156)
CBAP	contention based access period
CBC	cipher-block chaining
CBC-MAC	cipher-block chaining message authentication code
CBP	contention based protocol
CCA	clear channel assessment
CCDF	Complementary cumulative distribution function(#3359)
CCK	complementary code keying
CCM	CTR with CBC-MAC
CCMP	CTR with CBC-MAC Protocol
CCSR	centralized coordination service root
CCSS	centralized coordination service set
CF	contention free
CFP	contention free period
CID	Company ID
CP	contention period
CRC	cyclic redundancy code
CS	carrier sense
CSD	cyclic shift diversity
CSI	channel state information
CSM	channel schedule management
CSMA/CA	carrier sense multiple access with collision avoidance
CTR	counter mode
CTS	clear to send
CTS1	clear to send 1
CTS2	clear to send 2
CVS	contact verification signal
CW	contention window
DA	destination address
DBPSK	differential binary phase shift keying
DCF	distributed coordination function
DCLA	dc level adjustment
DCM	Dual carrier modulation
DEI	drop eligibility indicator
DELBA	delete block acknowledgment
DELTS	delete traffic stream
DFS	dynamic frequency selection
DFT	discrete Fourier transform
DIFS	distributed (coordination function) interframe space
DL	Downlink
DL	MU Downlink multi-user
DL	OFDMA Downlink orthogonal frequency division multiple access(#9230)
DL-MU-MIMO	downlink multi-user multiple input, multiple output
DLL	data link layer
DLS	direct-link setup
DLTF	Data Long Training field
DMG	directional multi-gigabit
DMS	directed multicast service
DMSID	directed multicast service identifier
DN	destination network
DO	DFS owner
DQPSK	differential quadrature phase shift keying
DR	data rate
DS	distribution system
DSAF	distribution system access function
DSCP	differentiated services code point
DSE	dynamic station enablement
DSM	distribution system medium
DSS	distribution system service
DSSS	direct sequence spread spectrum
DST	daylight saving time
DTI	data transfer interval
DTIM	delivery traffic indication map
DTP	dynamic tone pairing
Dp	desensitization
EAP	Extensible Authentication Protocol (IETF RFC 3748 [B42])
EAPOL	Extensible Authentication Protocol over LANs (IEEE Std 802.1X-2010)
EAS	emergency alert system
EBR	expedited bandwidth request
ECAPC	extended centralized AP or PCP cluster
ECS	extended channel switching
ED	energy detection
EDCA	enhanced distributed channel access
EDCAF	enhanced distributed channel access function
EDT	eastern daylight time
EHCC	extended hyperbolic congruence code
EIFS	extended interframe space
EIRP	equivalent isotropically radiated power
ELTF	Extension Long Training field
EOF	end-of-frame
EOSP	end of service period
EPD	EtherType Protocol Discrimination (IEEE Std 802-2014)
ERP	extended rate PHY
ERP-CCK	extended rate PHY using CCK modulation
ERP-DSSS	extended rate PHY using DSSS modulation
ERP-DSSS/CCK	extended rate PHY using DSSS or CCK modulation
ERP-OFDM	extended rate PHY using OFDM modulation
ESA	extended service area
ESP	estimated service parameters
ESR	emergency services reachable
ESS	extended service set
EST	eastern standard time
EVM	error vector magnitude
FCS	frame check sequence
FD-AF	full-duplex amplify-and-forward
FEC	forward error correction
FER	frame error ratio
FFC	finite field cryptography
FFE	finite field element
FFT	Fast Fourier Transform
FIFO	first in first out
FMS	flexible multicast service
FMSID	flexible multicast stream identifier
FOV	field of view
FSM	finite state machine
FST	fast session transfer
FSTS	fast session transfer session
FT	fast BSS transition
FTAA	fast BSS transition authentication algorithm
FTE	fast BSS transition element
FTM	fine timing measurement
FTO	fast BSS transition originator
GANN	gate announcement
GAS	generic advertisement service
GATS	group addressed transmission service
GCM	Galois/counter mode
GCMP	Galois/Counter Mode Protocol
GCR	groupcast with retries
GCR-A	groupcast with retries active
GCR-SP	groupcast with retries service period
GDB	geolocation database
GDD	geolocation database dependent
GFSK	Gaussian frequency shift key or keying
GI	guard interval
GID	group identifier
GMK	group master key
GNonce	group nonce
GP	grant period
GPRS	general packet radio service
GPS	Global Positioning System
GQMF	group addressed quality-of-service Management frame
GTK	group temporal key
GTKSA	group temporal key security association
HC	hybrid coordinator
HCC	hyperbolic congruence code
HCCA	HCF controlled channel access
HCF	hybrid coordination function
HD-DF	half-duplex decode-and-forward
HE	High efficiency
HEC	header error check
HELD	HTTP-enabled location delivery
HEMM	HCCA, EDCA mixed mode
HESSID	homogenous extended service set identifier
HIPERLAN	high-performance radio local area network
HPA	high power amplifier
HR/DSSS	high rate direct sequence spread spectrum using the long preamble and header
HR/DSSS/short	high rate direct sequence spread spectrum using the optional short preamble and header mode
HT	high-throughput
HT-GF-STF	high-throughput Greenfield Short Training field
HT-SIG	high-throughput SIGNAL field
HT-STF	high-throughput Short Training field
HTC	high-throughput control
HTTP	hyptertext transfer protocol
HTTPS	hyptertext transfer protocol secure
HWMP	hybrid wireless mesh protocol
HWMP	SN hybrid wireless mesh protocol sequence number
I/Q	in phase and quadrature
IBSS	independent basic service set
ICMP	Internet Control Message Protocol
ICV	integrity check value
IDFT	inverse discrete Fourier transform
IFFT	inverse Fast Fourier Transform
IFS	interframe space
IGTK	integrity group temporal key
IGTKSA	integrity group temporal key security association
IMp	intermodulation protection
INonce	initiator nonce
IPI	idle power indicator
IPN	IGTK packet number
IQMF	individually addressed quality-of-service Management frame
ISM	industrial, scientific, and medical
ISS	initiator sector sweep
IUT	implementation under test
IV	initialization vector
KCK	EAPOL-Key confirmation key
KDE	key data encapsulation
KDF	key derivation function
KEK	EAPOL-Key encryption key
L-LTF	non-HT Long Training field
L-SIG	non-HT SIGNAL field
L-STF	non-HT Short Training field
LA	Link adaptation(#4727)
LAN	local area network
LBIFS	long beamforming interframe space
LCI	location configuration information
LDPC	low-density parity check
LFSR	linear feedback shift register
LGR	legendre symbol
LLC	logical link control
LME	layer management entity
LNA	low noise amplifier
LP	low power
LPD	LLC Protocol Discrimination (IEEE Std 802-2014)
LRC	long retry count
LSB	least significant bit
LTF	Long Training field
MAC	medium access control
MAC_I	initiator mac address
MAC_P	peer mac address
MAF	MCCA access fraction
MBCA	mesh beacon collision avoidance
MBIFS	medium beamforming interframe space
MBSS	mesh basic service set
MCCA	MCF controlled channel access
MCCAOP	MCF controlled channel access opportunity
MCF	mesh coordination function
MCS	modulation and coding scheme
MDE	Mobility Domain element
MDID	mobility domain identifier
MFB	MCS feedback
MFPC	management frame protection capable
MFPR	management frame protection required
MFSI	MCS feedback sequence identifier
MGTK	mesh group temporal key
MIB	management information base
MIC	message integrity code
MID	multiple sector identifier
MIDC	multiple sector identifier capture
MIH	media-independent handover
MIMO	multiple input, multiple output
MLME	MAC sublayer management entity
MLPP	multi-level precedence and preemption
MM-SME	multiple MAC station management entity
MME	Management MIC element
MMPDU	MAC management protocol data unit
MMS	multiple MAC sublayers
MMSL	multiple MAC sublayers link
MPDU	MAC protocol data unit
MPM	mesh peering management
MRQ	MCS request
MSB	most significant bit
MSDU	MAC service data unit
MSGCF	MAC state generic convergence function
MSI	MRQ sequence identifier
MSK	master session key
MTK	mesh temporal key
MU	multi-user
MU-MIMO	multi-user multiple input, multiple output
MU-RTS	Multi-user request to send
MUEDCATimer	Multi-user EDCA timer(#3244)
N/A	not applicable
NAI	network access identifier
NAS	network access server
NAV	network allocation vector
NCC	network channel control
NDP	null data packet
NSS	number of spatial streams
NTP	Network Time Protocol (IETF RFC 1305 [B27])
NonERP	nonextended rate PHY
OBO	Orthogonal frequency division multiple access (OFDMA) backoff
OBSS	overlapping basic service set
OCB	outside the context of a BSS
OCT	on-channel tunneling
OCW	Orthogonal frequency division multiple access (OFDMA) contention window
OFDM	orthogonal frequency division multiplexing
OFDMA	Orthogonal frequency division multiple access(#3292)
OI	organization identifier
OM	Operating mode(#7051)
OMI	Operating mode indication(#5197)
OMN	Operating mode notification(#7051)
OSI	Open Systems Interconnection (ISO/IEC 7498-1:1994)
OUI	organizationally unique identifier
PAE	port access entity (IEEE Std 802.1X-2010)
PBAC	protected block ack agreement capable
PBSS	personal basic service set
PC	point coordinator
PCF	point coordination function
PCO	phased coexistence operation
PCP	PBSS control point
PCPS	PBSS control point service
PDU	protocol data unit
PER	packet error ratio
PERR	path error
PHB	per-hop behavior
PHY	physical layer
PHYCS	PHY carrier sense
PHYED	PHY energy detection
PICS	protocol implementation conformance statement
PIFS	point (coordination function) interframe space
PLME	physical layer management entity
PLMR/CRS	private land mobile radio/cellular radio service [US]
PLW	PSDU length word
PMK	pairwise master key
PMK-R0	pairwise master key, first level
PMK-R1	pairwise master key, second level
PMKID	pairwise master key identifier
PMKSA	pairwise master key security association
PN	packet number
PN	pseudonoise (code sequence)
PNonce	peer nonce
PP	polling period
PP	A-MSDU payload protected aggregate MAC service data unit
PPDU	PHY protocol data unit
PPE	PHY padding extension
PREP	path reply
PREQ	path request
PRF	pseudorandom function
PRNG	pseudorandom number generator
PS	power save (mode)
PSAP	public safety answering point
PSDU	PHY service data unit
PSF	PHY Signaling field
PSK	preshared key
PSM	power save mode
PSMP	power save multi-poll
PSMP-DTT	power save multi-poll downlink transmission time
PSMP-UTT	power save multi-poll uplink transmission time
PTI	peer traffic indication
PTK	pairwise transient key
PTKSA	pairwise transient key security association
PTP	TSPEC peer-to-peer traffic specification
PWE	password element of an ECC group
PXU	proxy update
PXUC	proxy update confirmation
QAB	quieting adjacent BSS
QACM	QMF access category mapping
QAM	quadrature amplitude modulation
QBPSK	quadrature binary phase shift keying
QLDRC	QoS long drop-eligible retry counter
QLRC	QoS long retry counter
QMF	quality-of-service Management frame
QPSK	quadrature phase shift keying
QSDRC	QoS short drop-eligible retry counter
QSRC	QoS short retry counter
QTP	Quiet time period(#9111)
QoS	quality of service
R0KH	PMK-R0 key holder in the Authenticator
R0KH-ID	PMK-R0 key holder identifier in the Authenticator
R1KH	PMK-R1 key holder in the Authenticator
R1KH-ID	PMK-R1 key holder identifier in the Authenticator
RA	receiver address or receiving station address
RADIUS	remote authentication dial-in user service (IETF RFC 2865 [B33])
RANN	root announcement
RAV	resource allocation vector
RCPI	received channel power indicator
RD	reverse direction
RDE	RIC Data element
RDG	reverse direction grant
RDP	Reverse direction protocol(#4727)
RDS	relay DMG STA
REDS	relay endpoint DMG STA
RF	radio frequency
RFC	request for comments
RIC	resource information container
RIFS	reduced interframe space
RLAN	radio local area network
RLQP	registered location query protocol
RLS	relay link setup
RLSS	registered location secure server
ROC	relay operation type change
ROM	Receive operating mode(#7051)
RPI	receive power indicator
RRB	remote request broker
RSC	receive sequence counter
RSN	robust security network
RSNA	robust security network association
RSNE	Robust Security Network element
RSNI	received signal-to-noise indicator
RSPI	receiver service period initiated
RSS	responder sector sweep
RSSI	receive signal strength indicator
RTS	request to send
RTT	round trip time
RU	Resource unit(#3293)
RX	receive or receiver
RXASSI	receive antenna selection sounding indication
RXASSR	receive antenna selection sounding request
RXSS	receive sector sweep
S-AP	synchronization access point
S-APSD	scheduled automatic power save delivery
S-PCP	synchronization PBSS control point
S0KH	PMK-R0 key holder in the Supplicant
S0KH-ID	PMK-R0 key holder identifier in the Supplicant
S1KH	PMK-R1 key holder in the Supplicant
S1KH-ID	PMK-R1 key holder identifier in the Supplicant
SA	source address
SA	Query security association query
SAE	simultaneous authentication of equals
SAP	service access point
SBIFS	short beamforming interframe space
SC	single carrier
SCA	secondary channel above
SCB	secondary channel below
SCN	no secondary channel
SCS	stream classification service
SCSID	stream classification service identifier
SDL	specification and description language
SDU	service data unit
SEMM	SPCA-EDCA mixed mode
SF	Scaling factor(#8181)
SFD	start frame delimiter
SI	service interval
SIFS	short interframe space
SKCK	STSL key confirmation key
SKEK	STSL key encryption key
SLRC	station long retry count
SLS	sector-level sweep
SM	spatial multiplexing
SME	station management entity
SMK	STSL master key
SMKSA	STSL master key security association
SMT	station management
SNAP	Sub-Network Access Protocol
SNR	signal-to-noise ratio
SNonce	supplicant nonce
SP	service period
SPA	supplicant address
SPCA	service period channel access
SPP	A-MSDU signaling and payload protected aggregate MAC service data unit
SPR	service period request
SPSH	spatial sharing
SQ	signal quality (PN code correlation strength)
SR	Spatial reuse(#8111)
SRC	short retry count
SRG	Spatial reuse group(#8111)
SS	station service
SSID	service set identifier
SSP	subscription service provider
SSPN	subscription service provider network
SSRC	station short retry count
SSW	sector sweep
STA	station
STBC	space-time block coding
STF	Short Training field
STK	STSL transient key
STKSA	STSL transient key security association
STSL	station-to-station link
STT	selective translation table
SU	single-user
SU-MIMO	single-user multiple input, multiple output
SYNC	synchronization
TA	transmitter address or transmitting station address
TAI	Temps Atomique International (International Atomic Time)
TB	Trigger-based(#6745, #6747)
TBTT	target beacon transmission time
TC	traffic category
TCLAS	traffic classification
TDDTI	time division data transfer interval
TDLS	tunneled direct-link setup
TFS	traffic filtering service
TID	traffic identifier
TIE	Timeout Interval element
TIM	traffic indication map
TK	temporal key
TKIP	temporal key integrity protocol
TLV	type/length/value
TMPTT	target measurement pilot transmission time
TOA	time of arrival
TOD	time of departure
TOM	Transmit operating mode(#7051)
TPA	transmission time-point adjustment
TPC	transmit power control
TPK	TDLS PeerKey
TPKSA	TDLS PeerKey security association
TPU	TDLS peer U-APSD
TRN-R	receive training
TRN-T	transmit training
TRQ	training request
TS	traffic stream
TSC	TKIP sequence counter
TSF	timing synchronization function
TSID	traffic stream identifier
TSN	transition security network
TSPEC	traffic specification
TTAK	TKIP-mixed transmit address and key
TTL	time to live
TTTT	target TIM transmission time
TU	time unit
TVBD	television band device [US]
TVHT	television very high throughput
TVWS	television white spaces
TX	transmit or transmitter
TXASSI	transmit antenna selection sounding indication
TXASSR	transmit antenna selection sounding request
TXE	transmit enable
TXOP	transmission opportunity
TXSS	transmit sector sweep
U-APSD	unscheduled automatic power save delivery
U-NII	unlicensed national information infrastructure
UCT	unconditional transition
UESA	unauthenticated emergency service accessible
UL	Uplink
UL	MU Uplink multi-user
UL	OFDMA Uplink orthogonal frequency division multiple access(#9231)
ULS	Universal Licensing System
UMRS	Uplink multi-user response scheduling(#4727)
UORA	Uplink orthogonal frequency division multiple access (OFDMA) based random access(#8142)
UP	user priority
UPH	Uplink power headroom(#4727)
UPSIM	unscheduled power save indication map
URI	Uniform Resource Identifier
URL	Universal Resource Locator
URN	Uniform Resource Name
UTC	Coordinated Universal Time
VHT	very high throughput
VLAN	virtual local area network
VoIP	voice over Internet Protocol (IP)
WEP	wired equivalent privacy
WLAN	wireless local area network
WM	wireless medium
WNM	wireless network management
WSD	white space device [EU]
WSM	white space map

Use Prologix USB-GPIB with Python (or any other language)

 This USB to GPIB adapter by Prologix is cheap and pretty neat. It uses an FTDI chip to interface with USB, so the device shows up as a COM port when connected to a computer. The FTDI driver is available on Windows, Linux and Mac OS, so most users can use these devices without worrying about finding drivers.

The programming is relatively easy, as long as you can communicate through COM port. Since it is a virtual COM port over USB, the Baud rate can be set very high. The command strings are sent through the virtual COM port, buffered, then sent over GPIB. Therefore, a command string has been written to the COM port does not mean it has reached the slave on the bus. This asynchronous nature can cause some unexpected behavior. For example, if we send *IDN? to an equipment on the bus, Pyserial write function returns as soon as this string is in the buffer of COM port. If we start to read from the bus right away, the equipment does not understand why it is set to TALK. To avoid this problem, a short delay should be inserted between writing to the equipment and reading from it.

Some queries may take time to complete because the slave needs to collect data samples, process the data, ... Consequently, the query may timeout and return empty or partial information. Increasing timeout may help the situation but with side effects. This is because there are two timeouts - GPIB timeout and COM (serial) port timeout. In addition, longer timeout will delay many normal operations. This problem can be easily solved by increase the delay mentioned above without touching timeouts. The GPIB slave cannot send the response until it is set to TALK, therefore no information will be lost if we do not start the read. In the sample code linked below, the delay can be simply controlled for each query, so it is trivial to adapt to different use cases.

One feature of the adapter often causes problems is read-after-write. This is set by writing "++auto 1" to COM port. Although it is convenient in theory, some instruments report error when being set to TALK by some commands that do not require an answer. Therefore, it is recommended to disable this feature and read explicitly by "++read eoi" command.

A simple class written in Python can be found at 

https://bitbucket.org/qiang_self/prol_gpib/src The code has been tested on Windows 7 with Python 2.7.11 and 3.5.2.

Easy way to run python script in Conda activated environments in Windows

Conda is a great tool to setup python and various packages/languages. It provides easy method to switch between environments, e.g., one can easily switch between python 2.7 and python 3.5 without resorting tedious hacks and tricks. However, when using it in Microsoft Windows, it is not as convenient as one wishes for.

In Windows, there are multiple ways to run a python script.

1. You can set the path to python.exe in your PATH variable, then type "python path_to_your_script". Although you don't have to type the path to your python installation, you have to type the path to your script every time. You can use the script in the same directory as your command line environment, but this is an inconvenient restriction.
2. In addition to setting the path to python.exe in PATH variable, one can also set the path to your scripts in PATH variable. Some distributions of python works well and you simply need to type "your_script_name" and Windows will call python.exe to run it. This did not work for me at least on Anaconda2-2.5.0-Windows-x86_64. I had to manually associate files with .py extension with python.exe installed by Anaconda. While this did work, there is a new problem - it always uses the root environment. In my case, the root environment is python 2.7. I installed python 3.5 through Conda and named it py35. After "activate py35", and run python.exe --version, it shows python 3.5. However, when I run my script, it still shows python 2.7. This is because when I type the name of the script, Windows loads the python.exe file (version 2.7 in this case) that I associated earlier. 

In order to take advantage of Conda's capability of switching environment, I tried a a slightly different approach. I created a file called run_python.bat and saved it in the same directory as my python scripts. You can save it anywhere as you like, just make sure to add the path to it in your PATH variable. Inside this file, there is only one line - @python.exe  %* Then I associated .py extension with this new batch file. Note that I did not put the path to python.exe in the batch file. It is intentional. Without an absolute path specified, Windows searches for it. As Conda switches the environment, the python.exe found by Windows will be different, which serves my purpose perfectly. By default, when you associate an file extension with a program, there is an entry created in Windows registry. Run regedit.exe, search for an entry called "run_python.bat" after you have associated the .py extension with it. There should be "shell:open:command" for this entry. The default value for command is "path_to_your_directory\run_python.bat" "%1", change it to "path_to_your_directory\run_python.bat" "%1" %* so that the arguments can be passed to your python script properly.

That's it. A simple trick that worked for me.

Vacation in Yosemite, Sequoia and Kings Canyon

We went to Yosemite National Park, Sequoia and Kings Canyon National Parks in mid June 2013 and stayed at Tenaya Lodge and Wuksachi Lodge respectively. The climate was perfect for light hiking and water was abundant in water falls, streams, and lakes. Among all the vista spots we visited, Tenaya Lake along Tioga Pass was our favorite. Tioga Pass was a beautiful scenic drive definitely worth spending time on it.

Bridalveil Fall

Mirror Lake

Mirror Lake down stream

More photos can be found on my website or on flickr.

Eee Pad Transformer TF101 Honeycomb 3.2.1 Battery Drain Solution

Asus Android Tablet - Eee Pad Transformer TF101 is one of the best tablets available in market as of Oct 2011. Not only because of its reasonable price, but also because of its IPS LCD panel, and its smart keyboard/dock design. However, one of its drawbacks is the relatively short battery life without the extra battery inside the dock.

What makes the situation worse is after the recent upgrade to Honeycomb 3.2.1, the tablet started to drain much more power than it used to do, and that is regardless the dock being connected or not. I tried suggestions found online using Automateit or Auto airplane mode, but the system was still using a lot of power. It seemed that the system never went to sleep.

While I was suffering with this bug, I came across a "solution" accidentally and would like to share it with all affected users. By inserting a microSD card into the slot on the tablet itself, this problem went away! This can be easily verified when a dock is connected - the light next to charging connector blinks even when the tablet is supposed to be in sleep. After the insertion, the light stops blinking.

I hope Asus can solve this problem in their firmware soon so users who do not know this trick will be saved. However, till Asus fix the problem, this trick can help us use the tablet as it is intended to be.

P.S. My tablet and dock are B60 version, so I cannot say whether it will work on your hardware if it is a different version.

Update Nov 9, 2011
With the latest firmware update (Android is still 3.2.1), this battery drain issue has been fixed. No need to try the trick here anymore.

If you would like to improve the battery life further when the tablet is in sleep, use Auto Airplane mode app to set the tablet into airplane mode when the screen is off. The reason this extends battery life is that the system fetches information over the internet from time to time while it is in sleep mode, which consumes extra power. However, if you are using VoIP software and would like to receive incoming calls, you cannot and should not use this app.

When the tablet is docked, it seems that disabling the touch pad improves battery life further in sleep mode.

Receive voicemail and fax through internet for free in the US

Although we are living in an age of internet and text messages, occasionally we do need to be communicated with voice messages or faxes. For many people like me that do not have a landline phone at home, this can be difficult. In other situations, e.g., for privacy reason, we do not want to release our home phone number, it will be very convenient if we can receive voicemails and faxes through internet. In addition, it is much easier to keep an electronic copy of the fax than keeping the paper copy, not to mention redistribution is effortless with the electronic copy.

To my surprise, I came across this free service that provides a phone number in the US for us to receive voicemails and faxes. It is a real phone number, not an extension number! k7.net forwards voicemails and faxes to any email address that you specify. If you have control over your email accounts, you can also set up an alias that forwards incoming emails to multiple actual email addresses. If you are running a small business, you can set up an alias called fax@yourdomain and forward emails to all of your users. Sign up is very simple.

There are 2 limitations with this free service - (1) it assigns you a Washington State phone number, (2) it expires if there is no activity in 30 days.

One issue that you need to watch out is the format of the fax is TIFF that supports non-square pixels. Most fax machines send out images using these non-square pixels which makes the images look odd (wide and short). Gmail users can view (not the preview image when you read the email) these files online without any distortion and the default image viewer coming with Microsoft Windows can view them. I believe IrfanView also supports this format. As far as I can tell, for Linux users Okular and Evince can also display them correctly. Other OSes or viewers may have trouble with these images. The trick I use to assure compatibility is to convert the TIFF file to PDF using ImageMagick. This tool is included in almost every Linux distribution and can be installed on other OSes as well.

San Jose Airport

San Jose Airport (airport code SJC) is one of my favorite airports when I travel by air. It is clean and well decorated, with reasonable security crew that was more efficient and polite than some other bigger airports. A lot of passengers are on business trips, therefore you will not see many tired people with excessive luggage. The airport had going been through renovations for years, now it finally stops giving you the impression of walking through a construction zone. There is also free Wi-Fi access so you can stay online while waiting for the flight.

Another favorite of mine is John Wayne Airport in Orange County (airport code SNA). It is even smaller. The free Wi-Fi access is not as reliable as SJC, but you do not need to walk as long to get to the gates as with SJC.