Any question about Wireless Technology [Archive]

lordofearrings

10-08-2002, 06:20

- what is the phase lock loop frequency in Nokia highband TDMA moble phone and how it work?

A phase-locked loop (PLL) is an electronic circuit with a voltage- or current-driven oscillator that is constantly adjusted to match in phase (and thus lock on) the frequency of an input signal. In addition to stabilizing a particular communications channel (keeping it set to a particular frequency), a PLL can be used to generate a signal, modulate or demodulate a signal, reconstitute a signal with less noise, or multiply or divide a frequency. PLLs are frequently used in wireless communication, particularly where signals are carried using frequency modulation (FM) or phase modulation (PM). PLLs can also be used in amplitude modulation (AM). PLLs are more commonly used for digital data transmission, but can also be designed for analog information. Phase-locked loop devices are more commonly manufactured as integrated circuits (ICs) although discrete circuits are used for microwave.
A PLL consists of a voltage-controlled oscillator (VCO) that is tuned using a special semiconductor diode called a varactor. The VCO is initially tuned to a frequency close to the desired receiving or transmitting frequency. A circuit called a phase comparator causes the VCO to seek and lock onto the desired frequency, based on the output of a crystal-controlled reference oscillator. This works by means of a feedback scheme. If the VCO frequency departs from the selected crystal reference frequency, the phase comparator produces an error voltage that is applied to the varactor, bringing the VCO back to the reference frequency. The PLL, VCO, reference oscillator, and phase comparator together comprise a frequency synthesizer. Wireless equipment that uses this type of frequency control is said to be frequency-synthesized.

Since a PLL requires a certain amount of time to lock on the frequency of an incoming signal, the intelligence on the signal (voice, video, or data) can be obtained directly from the waveform of the measured error voltage, which will reflect exactly the modulated information on the signal.

lordofearrings

10-08-2002, 06:39

Hey 7604,
Your sentence "I have around ten thousand questions about wireless techology range from general to technical" seems nut to me. Answering a question right is hard, but raising questions is hella easy, 7604. You can copy questions from books, internet,... everywhere to post on here. So don't try to play like a fool here.

I only reply to those who are willing to learn. YOU ARE NOT IN THIS CASE, 7604.

7604

10-08-2002, 11:15

lordofearrings

10-08-2002, 13:49

It's all right.
I know you got lots of experience in your working field. And I can guess your age too. Of course you can ask as many question as you like based on your knowledge. However, you ask but you don't need answers. As a result, you are a BIG DIFFERENCE in this forum... hehe... another meaning... kidda show up.
Forget all da things...
Nice to know ya too.

Dinhnq

10-08-2002, 17:28

hey!
760.. la con ADC bao nhieu bit vay, dua ti thoi toi cung rat quan tam ve van de wireless, cho hoi mot chut con PLL co the mua o dau vay, cac ban co tai lieu ve no khong cho minh muon tham khao mot chut .
thank (biet moi cau tieng anh nay thoi, thong cam nhe)

James Nguyen

11-08-2002, 03:14

Chao Cac Ban:
Neu Anh ngu khong phai la tro ngai cho cac ban, toi xin gioi thieu voi cac ban mot so web sites nay de cac ban rong duong nghien cuu: http://www.sysopt.com/ (Gom hon 35,000 thanh vien chuyen ve nhung cau hoi lien quan den CCTT) va http://www.pcguide.com/

thiensu

06-09-2002, 16:36

Hi everybody!

If you know any links , e-books that tell about telecommunication technology.
Please share to me and everybody to using.

Thanks and regards.:D

monkey

06-09-2002, 17:16

I have some but they were encrypted. So, if you can recover password, I shall send you the file :D

monkey

06-09-2002, 17:19

and, if you can read online for long time, try this

www.netlibrary.com

username: c98vta1
password: password

many new books (even published in 2002)

namntj

28-09-2002, 12:01

Hey man,

Can you show me some links to documents for CDMA2000-3x signal processing? Do you have simul programs for that?

lordofearrings

30-09-2002, 01:09

I got some simul programs for this kind CDMA. But I cannot find them now (lost somewhere in my company computers).
Try this link:
http://searchnetworking.techtarget.com/sDefinition/0,,sid7_gci505555,00.html

Hope this helps

namntj

01-10-2002, 11:44

Hey,

Thanks for the link! There are some info for cdma2000-1x. But that site contains definitions only! What I wanna find is some real simul programs... Could you look for the lost programs, please?

Kev

17-10-2002, 17:48

Bài viết được gửi bởi lordofearrings
If any one has any question about wireless technology, go ahead and raise your question, I would be happy to answer all (remember: all questions are in English).

do you know anything in WAP ? I'm honest :o

lordofearrings

23-10-2002, 12:53

Yes, Wireless Access Port; or Wireless Application Protocol. What do you want to know?

Kev

25-10-2002, 22:35

well, create a database using perl, where people after they login from the wap phones (palms), they can access their own data, and all data can keep track of a daily reacord

how's about that sound :)

lordofearrings

27-10-2002, 14:04

Kev,
I think this is one of variable jobs that PDA programmers do. I don't do programming, but deal with wireless hardware stuffs. However, if you really need such programs you mentioned or any other kinds, I will surely ask my colleagues for help.

Later

venus

27-10-2002, 19:42

trùi, shock quá, anh Hai nói toàn tiếng Anh :( híc...

Kev

03-11-2002, 17:10

lordofearrings, there are no program to build those databse.... the only need: you must be a Perl super... not only Perl, other languages are required as well

wireless hardware ??? you mean like wireless phones or palms ??? you deal with htose stuffs ??? so you mean you're selling cell phones, not good at coding things :)

lordofearrings

05-11-2002, 01:26

to kev,
wireless hardware refers as components that create cellular phones, palms, satellites, radar and digital system communications. Wireless hardware stuffs are not cell phones or palms themselve

Bài viết được gửi bởi Kev
... you're selling cell phones.... <---- I do'nt do business lol

Thorn Bird

21-11-2002, 14:05

Chao Ban Lordofearings:
Ban co the giai thich dum ve van de UNLOCK mot dien thoai di dong khong? Nhung hieu nao, kieu nao (model) co the lam duoc va kieu nao thi khong? Cam on ban rat nhieu. Than ai.

lordofearrings

21-11-2002, 17:27

Chào bạn Thorn Bird. Unlock một đtdđ nơi bạn đang ở (ví dụ US) để khi bạn đi du lịch đến những nước khác bạn cũng có thể xài được (nếu nước đó cùng mạng điện thoại bạn đang xài). Mình chỉ nói những đt ở US có thể unlock thôi nhé, và mục đích unlock là để du lịch về VN xài được. Tất cả các loại đtdđ ở US co' mạng GSM/GPRS 900/1800/1900 (mạng GSM 900 này đem về VN xài được) thì đều unlock được. Những đt loại này của dịch vụ của Cingular, T-Mobile, và GSM của AT&T. Một số model là: Motorola V60 của T-Mobile; Nokia 8890, Sony Ericsson T68, T68i, Siemen S40 của Cingular; Sony Ericsson T68i của AT&T mạng GSM và Nokia 7210 mới ra, ... vẫn còn 1,2 models nữa nhưng mình không nhớ.
Trước khi về VN bạn có thể gọi tổng đài dịch vụ đtdđ của bạn để unlock (free). Mình nghe nói ở VN cũng unlock được, có không vậy?

Thân

monkey

21-11-2002, 19:08

nhà cung cấp dịch vụ đtđ của việt nam không có quản lý số EMI của đtdđ nên chỉ cần đtdđ của bạn dùng đúng tần số của nhà cung cấp là sài được. Việt nam sài GSM900

Neo

21-11-2002, 20:26

Sắp tới tôi sẽ post một số vấn đề liên quan đến 2G, 3G, WAP, WirelessLAN, radio-router(Mobile IP)
Các bác hỗ trợ tôi ha :)

lordofearrings

22-11-2002, 05:01

Ừa Neo post đi

lordofearrings

22-11-2002, 05:15

Bài viết được gửi bởi monkey
nhà cung cấp dịch vụ đtđ của việt nam không có quản lý số EMI của đtdđ nên chỉ cần đtdđ của bạn dùng đúng tần số của nhà cung cấp là sài được. Việt nam sài GSM900
Như vậy đtdđ ở Mỹ có tầng số GSM 900 đem về VN không cần unlock hả bạn?
Cám ơn bạn

tuyen976

26-04-2003, 09:03

CISCO WIRELESS LAN FOR FIELD ENGINEER.
CISCO WIRELESS LAN FOR SYSTEM ENGINEER.

Help me !!! Any one have these ? Please, send me the documments or web links related to these topics and how to pass these exams and get the certificate :-).
Thanks so much !

yuna_admirer

12-05-2003, 09:08

You can access PEC - Partner E-learning connection of Cisco for more information. This is required for CIsco Partner only, so in Cisco official website there won't be any information about that.

Actually, you can take a Cisco Specialization course of Wireless Engineering for such certification.

Cận

01-08-2003, 17:15

Chán quá, mấy anh mấy chị cứ xí xa xí xồ làm em chả hiểu gì cả.

th2000

25-09-2003, 21:55

I have studied bluetooth for a week, and i understood something of bluetooth technology. Now, i wanna program bluetooth application using Visual C++ or C#, anyone can help me?

772046

15-01-2004, 00:04

I have a laptop which has an internal modem. I travel alot so i rarely use my phone-line for getting on net. I just wanna know what kind of cellphone that supports calling ISP ? And how to plug it to my notebook? and how to use it ?! Thanks alot

rescuede

23-01-2004, 19:22

Vai dong ve new technology cua 2004

kehamchoi

19-03-2004, 08:02

so boring to try chat english in vietnam, i think i you try to play the fool like that out of the room and learn more you wanna. and now, please try become the vietnamese and take you knowleage out of your mind for anyone must use. thanks for reading

S3033030

12-04-2004, 18:38

I'm doing a report on this topic for work. Can u plz share your knowledge about this topic or even share the link where I can find tutorial 'bout IEEE 802.11?
Thankz

yokel2912

15-04-2004, 10:56

I'm cool with English, but if you can type Vietnamese, please do!

nes

27-09-2004, 08:59

Hix, toàn post tiếng Anh sao :(
THôi cho em hỏi 1 fát. Với Mobile IP, khi một máy tính muốn truyền tin đến một Mobile Node, nó phải gửi một gói tin với địa chỉ là IP fix của MN đó, gói tin sẽ được chuyển đến HA rồi qua tunnel từ HA đến MN. TUy nhiên nếu cái máy tính (sender) ở rất gần cái MN thì việc truuyền xảy ra như thế nào, có nhất thiết phải qua HA không ?.? Mấy đại ca giải thích = tiếng Việt hộ em cái :D thanx

nes

12-11-2004, 10:01

hix mãi ko ai trả lời a`...
THôi tự trả lời vậy :D
Khi một máy tính(corespondent node: CN) muốn gửi đến một Mobile Node (MN) trong mạng wireless, CN sẽ gửi đến home agent tại mạng gốc của MN yêu cầu về địa chỉ của MN, Home Agent sẽ gửi cho CN thông tin về MN (địa chỉ COA của MN) khi đó gói tin gửi từ CN đến MN sẽ có địa chỉ đích là địa chỉ COA của MN, gói tin sẽ được gủi thẳng tới địa chỉ này do đó ko bị trễ, đỡ tốn băng thông.
ok?.?

quỷ kiếm

16-11-2004, 08:26

UMTS

12-03-2005, 23:27

hic...WirelessTechnology are excited topics in many forums around the world. But i do not know why there are fewer real good question at here ? Information and Telecommunications Technology will converge together in near future, i think it means there isn't difference between IT Engineer and Telecoms Engineer... :cool:

yuna_admirer

13-03-2005, 00:20

Yup, that's true pal, and Networking Engineer (instead of IT engineer) is best to be evoled from a Telecoms Engineers.

trieu_tulong

14-03-2005, 08:59

Công ty mình trang chuẩn bị triển khai mạng không dây, hiện tại mình có ba sự lựa chọn phần cứng(access point) . một là sản phẩm của compex (WPE54G) hai là sản phẩm của linksys (WRT54G) ba là một số sản phẩm trendnet (TEW-431BRP,TEW-411BRP+,TEW-410APB,TEW-410APB+). Giám đốc của mình muốn biết về chất lượng của từng loại sản phẩm (Diện tích phủ sóng, Số lượng use, Chất lượng đường truyền). Mình đã vào các website của các sản phẩm này nhưng ngoài các thông tin kỹ thuật ra ko có trang nào đề cập đến vấn đề mình quan tâm cả.
Mình muốn tham khảo ý kiến của bạn về ba dòng sản phẩm trên, cho mình một lời khuyên, nên dùng sản phẩm nào.
Theo bạn sản phẩm nào là hoạt động ổn định, và chất lượng nhất?
Mình muốn phủ sóng cho hai toà nhà 3 tầng nằm kề nhau. Access point dự kiến sẽ đặt ở tầng 3 vì hiện tại switch và modem ADSL đặt ở tầng này.
Nên chọn Linksys WRT54G/GS bởi vì sau khi flash nó với Sveasoft's Alchemy firmware (http://wrt54g.serwer.net/) thì TX power output sẽ được boost lên tới 250mW (cao nhất trong tất cả sản phẩm cùng loại trên thị trường). Hiện tại tôi đang dùng, phạm vi phủ sóng rất tốt. AP đặt ở lầu 2 cover tầng trệt và lầu 3 vô tư không bị trở ngại nào hết. Thêm vào đó bạn còn có Linux shell, IPtables, WPA, QoS... the whole nine yards.

Bạn nói rõ chút về cấu hình của công ty và mạng sắp deploy. Building 1 (B1) và building 2 (B2) cách nhau bao xa? Lý do chính để dùng mạng wireless là làm gì i.e web browsing, e-mail hay là chia xẻ tài nguyên.

yuna_admirer

14-03-2005, 13:52

Hi.

250mW vượt qua giới hạn an toàn cho phép.

Không phải cứ mW càng cao là càng tốt. mW càng cao ảnh hưởng absortion càng nhiều, tín hiệu càng dể lổi.

trieu_tulong

14-03-2005, 14:21

TX power adjustment is just one of the many great features that is available on this particular firmware (totally adjustable from 0 - 250mW) which happens to be Linux-based. As you all know, true FREEDOM which can only be found in open-source platforms has always offered network/system builders the flexibility needed to execute a wide variety of tasks with a limited budget (that is the actual cost of the hardware itself, nothing more), thus still maintaining the industry-strenght stability. Depending on the evironment/application, power output tuning which can only be done in Linux (to my knowledge there's no other way to do this), really extends the range of operation and the WRT54's radio is fairly sensitive. At the core of a wired or wireless network, noise plays a crucial part in netwok's stability, keeping the radio from being resync'ed which can lead to lower system's overall performance.
Anyway, this is just my 2 cents; no system can be deployed with a few limited facts such as these. Budget and equipment of choice are the main factors here. My suggestions simply imply the key advantages of this paricular router which, penny for penny, clearly outperforms all its counterparts available on the markett at the time being. If possible, WRT54GS would be the first choice due to the amount of RAM on-board (64MB) vs. that of WRT54G (32MB), more RAM is always better so there would be plenty of rooms for other things which, any network geeks would have appreciated it. Regards.

nguyenanhdat

19-03-2005, 15:21

i have a wireless NIC edimax 802.11g EW-7128g but i dont know to install its driver in RH9 (as i know vendor doesnt support driver for linux), so if anyone know about this, plz help me.

trieu_tulong

19-03-2005, 18:01

i have a wireless NIC edimax 802.11g EW-7128g but i dont know to install its driver in RH9 (as i know vendor doesnt support driver for linux), so if anyone know about this, plz help me.
This card uses the rt2x00 driver, get it here (http://rt2x00.serialmonkey.com/rt2400-1.2.2-b2.tar.gz). Read the installation instructions included, pretty much straight forward.

nguyenanhdat

21-03-2005, 12:05

thanh kìu very rất nhiều

cysquan

24-04-2005, 19:59

i got 1 question
does this below situation ever happen ??
i'm using laptop with centrino technology 802.11b, and my friend using a laptop equipped with a 802.11g wireless card. when we use internet at the same time, he always get most of the bandwidth. for example, if the connection speed is about 25kb/s, he got about 20kb/s, and i and my other friend who use laptop with centrino technology get the rest although he is further from the route than me.
how to overcome this problem ? can all we get 25kb/s when we use internet at the same time ?
thx very much for helping me ^^

trieu_tulong

25-04-2005, 02:36

Every Ap's design is different, so is the way it handles bandwidth distribution of the associated radios. Upgrade your AP to the latest firmware, set it to a new, least crowded channel and set it to use 802.11b (B-mode) only. If possible, set it to sync at a slower speed. On an average 802.11b wireless card (like the Orinoco/Lucent card), having it sync'ed @ 5.5Mbps instead of 11Mbps would leave you with 3dB gain, which in turn increases your range by a factor of 1/4. It ain't much but consider the advantage: the radios don't have to needlessly send negotiating traffic in every frame, (especially if you're on the fringe of a network), thus provides a much more stable and efficient link.

If your router locks up or the link is breaking quite a few times, consider lower your fragmentation threshold a little bit (default is 2346 = off). I dropped mine down to 1400 and it works just fine.

sene

26-04-2005, 23:01

Recently I heard people tell about Voice over Wi-Fi (VoWi-Fi). I've searched for docs related to this tech but i got nothing useful. Is there any one here can give me an overview on VoWi-Fi or a useful link? Sorry for my rather poor english!

Vì post ở đây nên em phải tuân thủ là "write my questions in English" nhưng thực sự thì đây là ddth.com của dân Việt mình nên em nghĩ là hãy viết bằng tiếng Việt -> Giữ gìn sự trong sáng của tiếng Việt!!

trieu_tulong

27-04-2005, 00:32

VoWi-Fi chỉ là VoIP hoạt động trên Wi-Fi network nơi VoIP gồm có phần cứng lẫn phầm mềm giúp mọi người dùng Internet làm đường dây để tải những cú điện thoại. VoWi-Fi là phiên bản không dây của công nghệ này được tạo ra để làm việc với những thiết bị không dây tương ứng của PDA's hay notebooks. Có rất nhiều người hỏi là tại sao lại không dùng cell phone, đơn giản và tiện lợi hơn nhiều nhưng thương nghiệp và những đoàn thể lớn tận dụng được cái lợi là tiết kiệm được cước viễn thông trong khi đó còn có được một mobile system mà cho họ reliable coverage indoors và chất lượng âm thanh cao hơn nhiều so với cellular network mà chỉ có VoWi-Fi đem lại mà thội.

sene

27-04-2005, 08:31

Cám ơn bác trieu_tulong nhé! Bác có biết nơi nào ở VN dùng công nghệ này ko vậy? Nếu bác có tài liệu nào về triển khai VoWi-Fi thì share cho anh em cùng đọc nhé!

alann

13-05-2005, 21:52

Sorry ... search một hồi thì thấy cái mục này... nên xin phép đặt lại câu hỏi ở đây. Xin lổi nếu làm phiền các bác:

1) Làm sao để dấu/khóa MAC address của NIC trong máy, cần software gì không hay Win XP đã có sẳn rồi, xin chỉ dùm.

2) Tư Vấn dùm: Làm sao trải rộng thêm tín hiệu không dây..

Tôi đang có gắn Wireless Networking trong nhà (DSL) cho 3 computers(A, B, C), nhưng tín hiệu rất yếu (hoặc mất luôn) khi để computer ở xa quá máy Wireless Modem (chổ này gắn vào computer A chính). Các máy (B, C) đều có Wireless Network Card bên trong.

Làm sao để có thể trải rộng (extend signal strength) thêm tín hiệu cho các máy B và C? xin đừng khuyên tôi chạy dây. Nếu bạn nào có tài liệu chỉ dẫn rỏ ràng xin cho biết.

Tôi có nghe nói có thể gắn thêm hộp Access Point/Bridge gì gì đó có thể làm được, nhưng không rỏ gắn thế nào... dốt đành dựa cột mà nghe thôi.

Xin được học hỏi kinh nghiệm các bác nào có làm qua rồi. Nếu có thể, gởi cc: tới email sau.

Thanh kiêu,
alann@hotmail.com

Nếu biết trước thằng LinkSys này tốt như thế thì tôi tậu nó rồi. Trong cái link Sveasoft's Alchemy firmware có nhiều firmware cho cái model này, download cái nào đây?

trieu_tulong

14-05-2005, 01:17

Sveasoft's Alchemy link (http://wrt54g.thermoman.de/). Tôi đang dùng final release, chạy tốt, chưa thấy bugs.

Bác để ý forum's rules, đừng cross-post.

alann

14-05-2005, 02:23

yeah... đành xin lổi admin và mọi người, vì mình cần info. thật gấp

cysquan

23-05-2005, 18:50

i have some questions:
1) in the wireless network connection status, at the activity, we can see "Sent", and "recieved". the number represents the packets we sent, and recieved, doesn't it ? then 1,000 for an example represents 1KB or 1000kb ?
i always got "sent" approximately equal "recieved" , every second, my pc sends about 5-6, and my pc recieved about 25-27 . my friend who use laptop with centrino technology seems not to have any problem, his speed connection speed still good. but when i download somthing, or just suring internet, it seems to be that i got all the bandwidth since his laptop turns to download things very slow , but actually in my pc, speed is just about 20kbs the speed it really slow, worse than dial up although i using ADSL. my base internet speed is about 256kbs. why it turn out to be like this ? how to improve the situation ?
thanks for helping me

trieu_tulong

24-05-2005, 07:39

in the wireless network connection status, at the activity, we can see "Sent", and "recieved". the number represents the packets we sent, and recieved, doesn't it ? then 1,000 for an example represents 1KB or 1000kb ?
This is just packets count, there's no known measurement.

speed is just about 20kbs the speed it really slow, worse than dial up although i using ADSL. my base internet speed is about 256kbs
Window$ clocks download speed in KBps, while DSL's bandwidth is measured in Kbps. We know that 1KB=8Kb, so do the math. In a network with no bandwidth/traffic control, prolonged massive downloads will degrade its performance.

The solution is simple, get a router that supports QoS and prioritize http traffic over ftp. As for downloading speed, well, you have to get a dfferent plan. 256kbps is translated into 32KBps, subtract bandwidth overhead, you'll end up with 27-28KBps max.

cysquan

24-05-2005, 15:27

This is just packets count, there's no known measurement.

Window$ clocks download speed in KBps, while DSL's bandwidth is measured in Kbps. We know that 1KB=8Kb, so do the math. In a network with no bandwidth/traffic control, prolonged massive downloads will degrade its performance.

The solution is simple, get a router that supports QoS and prioritize http traffic over ftp. As for downloading speed, well, you have to get a dfferent plan. 256kbps is translated into 32KBps, subtract bandwidth overhead, you'll end up with 27-28KBps max.

but i dont know why my pc still only got about 2 KBps although when i tested, only my pc is connected to the network, and there's no one else. moreover, the packets count that my pc has sent , and recieved in the first min after connected is about 1000 each although i simply openned a page such as www.vnn.vn
i tested with my laptop centrino technology, ADSL plan 256 kbps, i got 2KBps. when i tested with my friend's laptop, his laptop got 25KBps. so are there something wrong with my pc ?

edit: i have just tested the 2nd time, this time i useda software called "bandwidth monitor Pro" to monitor the download speed, i found out that the download speed always varies. from 2 KBps, it immediately dropped down to 0.1 or 0.2 KBps and then a second later it went up to 1.2-1.3 KBps then it might drop 0.* KBps again or go up to 2 or 3 Kbps. indeed, the speed changing every second and not stay about the about the same speed. why it happens ? is my laptop out of range of the router ?

trieu_tulong

24-05-2005, 16:39

gaixixon

24-05-2005, 17:03

trieu_tulong

25-05-2005, 01:54

Hi buddies, I've just posted my question in another thread then found this. Thanks a tons if you could help mẹ
I have 2 LAN connected by a cable. LAN "A" have 2 wired pc LA1 and LA2; LAN "B" that is a wireless hub consists of 2 pc LB1 and LB2.
I could read things in LAN "A" from LAN "B" by typing \\{ip of pc in LAN "A"} but could not access LAN "B" from LAN "A"
Tell me how to solve this plz..
It looks like you have 2 different subnets and traffic on the wireless side is NAT'ed through the AP. While the wirless users can make connections to any machines on the wire, connecting back through a NAT is difficult (unless your AP supports static port mappings but this is far from convenient). For example, if you're running a Window$ client on the wireless, the Network Neighborhood shows only other wireless clients, and not any machines on the wire since NAT effectively hides broadcast traffic thus making your wireless hosts less accessible to your wired hosts.

If this is the case, your choice is limited. Either turn on static port mappings or turn your AP into a bridge but it's only possible if the AP supports those features. BTW, what make/brand is your AP?

cysquan

25-05-2005, 05:19

Does your wireless card have the latest drivers/firmware? Try to transfer several files between your PC and your friend's using various protocol (samba, ftp...) and clock the transfer rate to make sure that your card is up to speed. The best way to find out if your PC's acting up is to boot off a live Linux CD and run the test again.

before i also thought about using linux cd to test, but i couldn't set up the wireless connection in linux. it seems that the version that i'm using doesn't support wireless connection.
i has updated to the lastest driver, but the situation still wasn't improved

i got a pics that i capture when i'm using bandwidth monitor pro, and downloaing. http://xs.to/xs.php?h=xs30&d=05213&f=pc.JPG
in my opinion, our pc might only send packages as long as we surfing internet or upload. but when i'm only dowloading, it looks like my pc still sends somethings every second.
thank you so much for your useful advices ^^

trieu_tulong

25-05-2005, 05:45

Try the latest Knoppix v.3.8. It has full support for Centrino notebooks.

Whether or not the host sends/receives data, the radio still sends out packets. They are just beacon broadcast, sync-negotiation traffic...helpful when troubleshooting. For example, when there are more sent packets than received ones, it usually indicates a bad link, noise errors or both because the radio has to keep re-sending packets.

cysquan

25-05-2005, 08:32

but not all of the links are bad. when i tried to ping the address such as yahoo! it had no loss. indeed, it sent 4 package, then it recieved 4 package. but when i using EI, or firefox, it not the same

khdam

25-05-2005, 21:19

Ti dang dung modem ADSL va access point hieu NETGEAR. Cac ban vui long huong dan cach lap day de try cap nhieu may.
Lam the nao de ngan cac truy cap ...chua?

alann

01-07-2005, 00:10

Tôi đồng ý với một số bạn trong này, mình nên giữ tiếng Việt đi, thứ 1st, giúp các bạn khác (không biết nhiều tiếng Anh) học hỏi kinh nghiệm của mình. Thứ 2nd, tự giúp bạn trau dồi thêm tiếng Việt và giữ cái forum ddth VN này hoạt động đúng với cái tên của nó. Tôi cũng là dân VN đã ở Mỹ rất lâu, nhưng lại không thích "học" tiếng Anh trong này.

Chúc vui.