week 6: NETWORK TOPOLOGY

network t0p0l0gy is an arrangement, mapping 0f the element like a links and n0des. netw0rk t0p0l0gy asl0 kn0wn as lay0ut 0r design. netw0rk t0p0l0gy may be physical 0r l0gical.

• physical t0p0l0gy refers t0 the physical design 0f a netw0rk including the devices, l0cati0n and cable installati0n.
• linear bus, star, star wired ring, tree

• l0gical t0p0l0gy refers t0 h0w data is actually transferred in a betw0rk as 0pp0sed t0 its phusical design.
• like a s0ftware

= > physical t0p0l0gy relates t0 a c0re netw0rk whereas l0g0cal t0p0l0gy relates t0 basic netw0rk.

• n0des is a c0mputer that relate the devices.

LINEAR BUS

• c0nsists 0f a c0ntinu0us length 0f cable that c0nnects tw0 0r m0re device t0gether.
• a bus called a backb0ne netw0rk.

• 0n the bus netw0rk, 0nly 0ne c0mputer can transfer inf0rmati0ns at a time.
• the inf0rmati0ns m0ves thr0ugh the entire length 0f the cable.
• each end 0f the cable 0n the bus netw0rk must have a TERMINAT0R.
• terminat0r are a device that abs0rb the signals transmitted 0n a netw0rk cable.

THE ADVANTAGES 0F LINEAR BUS

• easy t0 c0nnect
• require less cable
• setup  0f a bus netw0rk is simple.
• 0ften used t0 c0nnect a few c0mputers l0cated in a small area, such as an 0ffice.

THE DISADVANTAGE 0F LINEAR BUS

• when adding a c0mputers t0 a bus netw0rk, the cable must be br0ken t0 extend the cable and attach the c0mputer.
• the 0ther c0mputer 0n the netw0rk cann0t exchange inf0rmati0n whike the cable is br0ken.
• if 0ne 0f the device is br0ken, the wh0le device will be br0ken.
• large bulding d0es n0t used linear bus.

STAR NETW0RK 

• c0nsists 0f individual c0mputer c0nnected t0 a centre p0int 0n the netw0rk

• each c0mputer is c0nnected t0 a central netw0rk c0nnect0r, called a hub.
• the inf0rmati0n that transfer fr0m 0ne c0mputer t0 an0ther 0n the netw0rk passed thr0ugh the hub.
• each c0mputer must be relatively cl0se t0 the netw0rk hub.
• cable length between a c0mputers and the hub sh0uld be less than 100 meters.
• hubs c0mm0nly c0nnect 4, 8, 0r 16 c0mputers t0gether.
• it is g0od t0 used at large bulding.

THE ADVANTAGES 0F STAR NETW0RK

• easy detect fault
• easy t0 add new w0rkstati0n
• easy t0 install & wire
• the netw0rk d0es n0t need t0 be shut d0wn when new c0mputers are c0nnected

THE DISADVANTAGES 0F STAR NETW0RK

• if 0ne hub is br0ken, the wh0le n0des are br0ken t0o.
• large am0unts 0f cable are used.
• each c0mputer must be c0nnecting t0 a netw0rk hub, an expensive c0mp0nent

TREE NETW0RK

• c0mbinati0n 0f linear bus and star netw0rk

NIC (NETW0RK INTERFACE C0NTR0LLER)

• c0mputer hardware c0mp0nent that c0nnects a c0mputer t0 a c0mputer netw0rk.
• c0mm0nly implemeted 0n expensive cards that plug int0 a c0mputer bus

NOS (NETWORK OPERATING SYSTEM)

• reffered t0 as th Dial0guer; is the s0ftware that runs 0n a server and enables the server t0 manage data, users, gr0ups, security, applicati0ns and 0ther netw0rking functi0ns.
• design t0 all0w shared file and printer access among multiple c0mputers in a netw0rk, typically a l0cal area netw0rk (LAN), a private netw0rk 0r t0 0ther netw0rk.
• the m0st p0pular NOS are Microsoft Windows Server 2003.

REPEATER

• an electr0nic devices that receive a signal and transmits it at a higher level 0r higher p0wer, 0r 0nt0 the 0ther side 0f an 0bstructi0n, s0 that the signal can c0ver l0nger distances.
• the functi0n is:
• t0 receive a netw0rk signal f0rm 0ne LAN terminal cable segment and t0 regenerate and retransmit the signal as it is in its 0riginal strength 0ver a  0ne 0r m0re 0ther cable segment.
• regenerates the strength 0f the signal bef0re transmitting

NETW0RK SWITCHES

• c0mputer netw0rking device that c0nnects netw0rk segments 0r netw0rk devices.
• the term c0mm0nly refer t0 a multiple-p0rt netw0rk bridge that pr0cesses and r0utes data at the data link layer.

C0NCENTRAT0R

• pr0vide c0mmunicati0n capability between many l0w-speed, usually asynchr0n0us channels and 0ne 0r m0re high-speed, usually synchr0n0us channels.
• a device that c0nnects a number 0f links with 0nly 0ne destinati0n
• the main functi0n is t0 make a kink 0f l0ad balancing between tw0 0r m0re servers c0nnected t0gether, data distributi0n is d0ne acc0rding t0 the server pr0cessing rate.

ETHERNET

• has largely replaced c0mpeting wired LAN techn0l0gies.
• devude a stream 0f data int0 individual packets called FRAMES
• each frame c0ntains s0urce and destinati0n addresses and err0r-checking data; damaged data can be detected and re-transmitted.
• used c0axial cable as a shared medium.
• later the c0axial cables were replaced by twisted pair and fibre optic links in c0njuncti0n with hubs 0r switches.

L0CAL TALK

• a system 0f shielded twisted pair cabling, plugged int0 self-terminating transceivers, running at a rate 0f 230.4 kbit/s.
• its sl0s. at 230.4 kbit/s, its faster than a m0dem, but at 1 MB/min, it takes f0rever t0 m0ve large files 0r d0 backup 0ver the netw0rk.
• it gets c0ngested. all inf0rmati0n is br0adcast t0 the entire netw0rk, s0 a few heavy userd can bring it t0 its knees. the m0re users, the w0rse it gets.
• its a daisy chain f0rm 0ne device t0 the next t0 the next. if the wiring g0es bad, y0u end up with tw0 netw0rks that can't talk with each 0ther.

T0KEN RING

• l0cal area netw0rk pr0t0c0l which resides at the data link layer (DLL) 0f the OSI m0del.
• it uses a special three-byte frame called a t0ken that travels ar0und the ring.
• t0ken-p0ssessi0n grants the p0ssess0r permiti0n t0 trasmit 0n the m0dem.
• t0ken ring frames travel c0mpletely ar0und the l0op.

week 5: c0mputer netw0rking

C0mputer netw0rking is the c0nnecti0n with 0ne t0 ant0her c0mputer t0 enable them c0mmunicate each 0ther. C0mputer netw0rk als0 as the way t0 share hardware, s0ftware and data as well as t0 c0mmunicate with 0ne an0ther. There are a few 0f netw0rk classificati0n which is LAN, WAN, MAN, PAN and s0 0n.

LAN is sh0rt f0rm fr0m L0cal Area Network. It is work as a c0vers relatively small g0egraphical such as in a h0me, sch0ol and 0ffice area.

WAN is Wide Area Netw0rk were covers large ge0graphical area. It consist 0f tw0 0r m0re LAN c0nnected t0gether using c0mmunicati0ns techn0l0gy internet is the largest WAN.

MAN is Metr0p0litan Area Networks. The netw0rk design t0 service a metr0p0litan area like a city. It was c0nsist 0f multiple LAN and the size is between LAN and WAN.

PAN is a Pers0nal Area Netw0rk. It is w0rked as a pers0nal device like printer, m0bile devices and s0 0n. The way netw0rk are w0rking is thr0ugh wired 0r wireless.

0n the netw0rking, there are have s0me c0mp0nents t0 make c0mputer w0rk as well. The c0mp0nents can be categ0ries:

1. Terminals, w0rkstati0ns, c0mputer and 0ther devices (end c0de)

1. Data s0urces and destinati0ns
2. Example is pers0nal c0mputer, terminal, w0rkstati0ns, c0mputers and aut0matic teller machines.

2. transmissi0n Media (f0r transmitting data and c0ntr0l signals)

1. Transmit data in a netw0rked envir0nment.
2. Divided by 2 types

                   i.      B0unded/guided: twisted pair, c0axial, fibre 0ptics

                   ii.      Unb0unded/unguided (air/vacuum): satellite c0mmunicati0n, micr0wave radi0, infrared signals

3. s0ftware t0 c0ntr0l data transmissi0n

1. Inf0rmati0n, data 0r pr0gramming used-c0mmunicate/c0nnect t0 0ne and an0ther.
2. share inf0rmati0n

4. netw0rk electr0nics (intermediate devices f0r r0uting data fr0m s0urce t0 destinati0n)

1. Act as interface between different transmissi0n media/c0mmunicati0n pr0t0c0l
2. Example: hub, r0uter,switch, bridge, gateway.

• HUB :
•  device f0r c0nnecting multiple internet device t0gether and making them act as a single netw0rk segment.
• has multuple input/0utput p0rts
• w0rks at the physical layer 0f the OSI m0del

• ROUTING
• pr0cess 0f selecting paths in a netw0rking al0ng which t0 send netw0rk traffic.
• perf0rmed at teleph0ne netw0rk (circuit switching), electr0nic data netw0rks and transp0rtati0n netw0rks.
• the functi0n :
• manage the part al0ng which inf0rmati0n is f0rwarded within a netw0rk; facilitate c0mmunicati0n between c0mputers and internet.
• c0me in tw0 types: dynamic and static.
• dynamic is manage data traffic acr0ss the netw0rk; manage by r0uting pr0t0c0l.
• static is manuaaly c0nfigured by a netw0rk administrat0r wh0 pr0grams all 0f the necessary r0utes that are needed f0r data packets.

• GATEWAY
• called pr0t0c0l c0nverters, 0perate at any netw0rk layer.
• essential feature 0f m0st r0uters, alth0ugh 0ther devices can functi0n as a gateway

• BRIDGE
• device that f0ll0w the c0mputers 0n individual netw0rks 0r separate parts 0f a netw0rk t0 exchange inf0rmati0n.
• used t0 c0nnect a sma;; number 0f individual netw0rks t0 w0rk t0gether as 0ne large netw0rk.
• split an 0verl0ad netw0rk int0 small parts

• PRIVATE BRANCH EXCHANGE (PBX)
• swicth stati0n f0r teleph0ne systems
• c0nsists mainly 0f several branches 0f teleph0ne systems and its swicth c0nnecti0ns t0 and fr0m them.
• the functi0n:
• pr0vide 0ne single number taht external callers can use t0 access all pers0ns in a c0mpany
• distribute calls t0 empl0yerd in a answering team in an even way; using the Aut0mate Call Distributi0n (ACD) feature.
• all0w the user 0f cust0mized business greetings.
• pr0vide system call management features.
• transfer calls between internal extensi0n.

• BLUETOOTH VS INFRARED
• bluet0oth:
• wireless and aut0matic and 0ffers users with variaties 0f excellent features that has recreated the art 0f c0nnecti0n
• bluet0oth techn0l0gy w0rks by transmitting signals via l0w frequency radi0 signa
• the part 0f  c0mmunicati0n is appr0ximately w0rking 0n 2.45 gigahertz.
• the standard range is ar0und ten meters
• many  ways have c0ntributed much in c0nnecting individual systems with0ut being b0thered by bulk 0f the cables and wires.
• 
  
• infrared:
• 0ne t0 0ne pr0cess
• transmit  signals between the tw0 but n0t with an0ther separate system.
• w0rks 0nly 0n the line 0f sight principle where in 0ne has t0 p0int th infrared device directly t0 the h0st system t0 achive a desirable result.

• FM (Frequency M0dulati0n) radi0
• c0nvey inf0rmati0n 0ver a carrier wave by varying its instantane9us frequency.
• carry a stere0 signals
• used at ZHF radi0 frequencies f0r h9gh-firelity br0adcasts 0f music and speech
• frequency is varied, and phase m0dulati0n, in which the phase is varied.

• AM (Amplittude M0dulati0n)

• technique used in electr0nic c0mmunicati0n, m0st c0mm0nly f0r transmitting inf0rmati0n v0a radi0 carrier wave.
• w0rks by varying the strength 0f the transmitted signals in relati0n t0 th inf0rmati0n being sent.
• f0r example, change in signal strength may be used t0 specific the s0unds t0 be repr0duced by a l0udspeaker, 0r the light intnsity 0f televisi0n pixels.

week 4: DATA C0MMUNICATI0N

Data c0mmunicati0n is ability t0 transmit inf0rmati0n is very imp0rtant f0r current s0ceity including g0vernment agency,business pe0ple 0r even pers0nal needs by individuals. Data c0mmunicati0n may help people t0 give 0r get the inf0rmati0n even they are stayed near 0r far away and make easier t0 c0mmunicate each 0ther.

Data c0mmunicati0n can be divided by tw0 types 0f signal; anal0gue and digital signal.

ANAL0GUE SIGNAL

1.       1.   Anal0gue signal is like a human v0ice. It is f0rmed by c0ntinu0sly varying v0ltage levels that create a wave that can be grasped by an anal0gue transmitter like MICR0PH0NE.

       2.   This anal0gue signal features inv0lves 2 parameter;

a.       Frequency- number 0f c0mplete wave’s cycles. It is measured in Hertz (Hz) [cycle per sec0nd].

b.      Amplitude- wave’s height that measured in v0ltan (V) 0r decibel (dB).

DIGITAL SIGNAL

  

   1.Transmissi0n 0f binary electrical 0r light pulses that 0nly have tw0 p0ssible state, 0 and 1 [the language 0f c0mputer]

  2. Digital signal need to be change int0 anal0gue signal t0 be transmitted PSTN lines .

   3. The pr0cess 0f changing anal0gue t0 digital signal = m0dulati0n

   4. The pr0cess 0f changing back t0 anal0gue f0rm = dem0dulati0n

   5. M0Dem is the hardware that used in c0mputer t0 d0 this pr0cess.

An0ther that, data c0mmunicati0n als0 has data transmissi0n m0de. The data transmiss0n m0de divided by 2 categ0ries; parallel and serial transmissi0n.

1.       Parallel transmissi0n that a gr0up 0f bits is transmitted simultane0usly by using a separate line f0r each bit.

2.       Serial transmissi0n transmit all the bits 0ne after an0ther 0n a single line. This transmissi0n style is a bit sl0wer c0mpared t0 parallel transmissi0n; h0wever it is best suit data c0mmunicati0n needs t0 transmit data in a l0ng distance area.

  3.       Divided by 2 serial; Synchr0n0us and Asynchr0n0us transmissi0n.

a.       Synchr0n0us transmissi0n

               i.      A large gr0up 0f data is transmitted in bl0cks called by a FRAME

b.      Asynchr0n0us transmissi0n

             i.     Used when the bits are divided int0 small gr0ups (bytes) and sent independently.

         ii.      The gr0ups 0f bits can be sent at any time and the receiver never kn0ws when they will arrive, f0r example, a keyb0ard.

Data fl0w is 0ne 0f the data c0mmunicati0n. Data c0mmunicati0n between 2 pieces 0f equipment, the pr0cess 0f exchanging data can be d0ne in either three 0perati0n styles. The message s0urce will be called transmitter while the destinati0n where the message will be sent is called receiver t0 pr0vide easier understanding 0n h0w the data fl0w actually w0rk. The data fl0w are divided by 3; simplex, half-duplex and full-duplex

.

1.       Simplex

a.       Data 0r inf0rmati0n is transmitted in 0ne directi0n 0nly.

b.      The r0le 0f the transmitter and receiver are FIXED.

c.       Example: radi0, televisi0n

    2.       Half-duplex

a.       Message can fl0w in 2 directi0n, but never at the same time.

b.      0ne stati0n transmits inf0rmati0n t0 an0ther stati0n with0ut any interupti0n.

c.       The 0ther stati0n will resp0nse after that transmissi0n has been c0mpleted.

d.      Example: walkie-talkie

       3.       Full-duplex

a.       B0th stati0n can transmit and receive simultine0usly.

Multiplexing is a set 0f technique that enable m0re than 0ne device t0 c0mbine and send their signals simultane0uslt thr0ugh a single data link at the same time.

C0axial cable 0r c0ax, has an inner c0nduct0r surr0unded by a flexible, tubular insulting layer, surr0unded by a tubular c0nducting shield. The term c0axial c0mes fr0m the inner c0nduct0r and the 0uter shield sharing the same ge0matric axis. C0axial cable is used as a transmissi0n line f0r radi0 frequency signals. Its applicati0n include feedlines c0nnecting radi0 transmitters and receivers with their antennas, c0mputer netw0rk (internet) c0nnecti0ns, and distributing cable televisi0n signals.

Week 2 : telec0mmunicati0n and netw0rking (web searching)

0n this week, we are learned about web browser, search t0ols and searching technique.

Web br0wser is the s0ftware applicati0n that interact with text, image and 0ther inf0rmati0n typically l0cated 0n a web page at a website 0n the w0rld wide web (WWW) 0r a l0cal area netw0rk. There are many types 0f web br0wser such as yah0o, g0ogle chr0me, m0zilla firef0x, 0pera and Netscape. N0w a day, the fam0us web br0wser that pe0ple used is g0ogle chr0me. In my 0pini0n, g0ogle chr0me are quite fam0us because it was had l0t 0f inf0rmati0n when the user l0oked up ab0ut s0mething by using a keyw0rd. F0r example, the users just search ab0ut telec0mmunicati0n and netw0rking. When they click the butt0n “search”, all things ab0ut telec0mmunicati0n and netw0rking were appear. An0ther that, g0ogle chr0me give us s0me kind 0f advantages such as it was fast f0r l0oking the inf0rmati0n.

Searching t0ols are include by search engines, subject direct0ries, name direct0ries, meta-searchers and s0 0n.

1. web search engine is designs t0 search f0r inf0rmati0n 0n the W0rld Wide Web and PTF servers. The search results are generally presented in a list 0f results 0ften referred t0 as SERPS, 0r “search engine results pages”. The inf0rmati0n may c0nsist 0f web pages, images, inf0rmati0n and 0ther types 0f files. An0ther search t0ols is web drect0ry. A web direct0ry 0r link direct0ry is a direct0ry 0n the W0rld Wide Web. It specializes in linking t0 0ther web sites and categ0rizing th0se links. A web direct0ry is n0t a search engine and d0es n0t display lists 0f web pages based 0n keyw0rds; instead, it lists web sites by cater0ry and subcateg0ry. Subject direct0ries is like a URL. F0r example is www.telec0mmunicati0n.c0m. But name 0f direct0ries is a pr0vide by http://. F0r example is “http://www.lib.berkeley.edu/TeachingLib/Guides/Internet/SubjDirectories.html”.

2. what is meta-search? Meta-search is instead 0f getting results fr0m 0ne search engine, y0u will be getting the best c0mbined results fr0m a variety 0f engines, and n0t just any engines, but industry leading engines like G0ogle, Yah0o!, search, and Bing, as well as auth0ruty sites K0smix and Fandang0.

3. a l0cal search als0 0ne 0f the search t0ols. A l0cal search f0rms part 0f the c0nveyancing pr0cess and is carried 0ut t0 ascertain if there are any matters affecting a specific pr0perty 0r piece 0f land, such as any restricti0ns which a pr0spective purchaser w0uld want t0 kn0w ab0ut bef0re they decide t0 g0 ahead with a purchase. A l0cal search will generally c0nsist 0f b0th a search in the statut0ry register and 0ther specific inf0rmati0n ab0ut the pr0perty.

4. deskt0p search is the name f0r the field 0f search t0ols which search the c0ntents 0f a user’s 0wn c0mputer files, rather than searching the Internet. These t0ols are designed t0 find inf0rmati0n 0n the user’s PC, including web br0wser hist0ries, e-mail archives, text d0cuments, s0und files, image and vide0.

5. g0ogle search 0r G0ogle Web Search is a web search engine 0wned by G0ogle Inc. g0ogle search is the m0st-used search engine 0n the W0rld Wide Web, receiving several hundres milli0n queriws each day thr0ugh its vari0us services. g0ogle search c0nsists 0f a series 0f l0calized websites. the largest 0f th0se, the g0ogle.c0m site, is the t0p m0st-visited website in the w0rld. s0me 0f its features include a definiti0n link f0r m0st searches including direct0ry w0rds, the number 0f results y0u g0t 0n y0ur search, links t0 0ther searches and many m0re.

6. b0olean is the l0gic that c0mputers use t0 determine if a statement is true 0r false. There are 4 main b0olean 0perat0rs : AND,NOT, OR, and XOR. There are the example 0f h0w the 4 0perat0rs w0rk:

x AND y returns True if b0th x and y are true, 0therwise the expressi0n returns False.

NOT x returns True if x is false (0r null) and False if x is true.

x OR y returns True if either x 0r y 0r b0th are true; 0nly if they are b0th false will it return False.

x OR y returns True if either x 0r y are true, but n0t b0th. if x and y are b0th true and false, the statement will return False.

7. multitasking is a meth0d where multiple tasks, als0 kn0wn as pr0cesses, share c0mm0n pr0cessing res0urces such as CPU. In the case 0f a c0mputer with a single CPU, 0nly 0ne task is said t0 be running at any p0int in time, meaning that the CPU is actively executing instructi0ns f0r that task. Multitasking s0lves the pr0blem by scheduling which task may be the 0ne running at any time given, and when an0ther waiting task gets a turn.

8. plug-in is a set 0f s0ftware c0mp0nents that adds specific abilities t0 a larger s0ftware applicati0n. If supp0rted, plug-ins are c0mm0nly used in web br0wsers t0 play vide0,scan f0r viruses, and display new file types. Well-kn0wn plug-ins examples include Ad0be Flash Player, Quick Time, and Micr0s0ft Silverlight.

9. unif0rm res0urce l0cat0r 0r universal res0urce l0cat0r (URL) is a specific character string that c0nstitutes a reference t0 an internet res0uce. A URL is technically a type 0f unif0rm res0urce identifier (URI) but in many technical d0cuments and verbal discussi0ns URL is 0ften used as a syn0nym f0r URI.

10. clear hist0ry is free and p0werfull wind0ws dekt0p applicati0n t0 clean search hist0ry f0rm y0ur c0mputer. it is full reatured pr0gram that greatly surpasses m0st c0mmercial pr0grams 0ut there.

What does it clear :

• Clear search history (browser history)
• Clear typed URL-s (website address)
• Clear location bar history ( option to exclude URL-s from clearing)
• Clear cache (temporary internet files)
• Clear cookies (with option to exclude some cookies from deleting)
• Clear autocomplete forms and passwords
• Clear index.dat files
• Delete recent documents (in Windows)
• Delete run history
• Delete find computers history
• Delete Windows temporary files
• Delete Recycle Bin without recovery (shred it after deleting)
• Clear clipboard (memory space reserved for copy/paste operations)
• Clear Windows Open/Save dialog history
• Clear tracks from Ms Office, Word, Excel, Access, Power Point and Front Page
• Clear tracks from WinZip, WinRar, Windows Media Player, Wordpad, Media Player Classic

"clear hist0ry" is made to help users protect their privacy. Although the author did his best to make this application safe an reliable as possible he can not be held responsible by any potential damage caused by using Clear History software. We hope you will find this software useful, we would appreciate if you link to this web site.

it's all about telec0mmunicati0n and netw0rking

week 1 : what is c0mmunicati0n?

c0mmunicati0n is the activity 0f c0nveying inf0rmati0n. c0mmunicati0n has been delivered fr0m the Latin w0rd "c0mmunis", meaning t0 share. c0mmunicati0n requires a sender, a message, and an intended recipient, alth0ugh the receiver need n0t be present 0r aware 0f the sender's intent t0 c0mmunicate at the time 0f c0mmunicati0n.; thus c0mmunicati0n can 0ccur acr0ss vast distances in time and space. c0mmunicati0n requires that the c0mmunicating parties share an area 0f c0mmunicative c0mm0nality. the c0mmunicati0n pr0cess is c0mplete 0nce the receiver has underst0od the message 0f the sender. feedback is critical t0 effective c0mmunicati0n between parties.

** c0mmunicati0n is imparting, c0nveying 0r exchange 0f th0ughts messages, ideas, kn0wledge 0r inf0rmati0n by sign and s0und like speech, signals, writing 0r behavi0r.

           what is TELEc0mmunicati0n?

   (tele = far 0ff)

telec0mmunicati0ns refers t0 the transfer 0f data (c0mmunicati0n) fr0m a transmitter t0 receiver acr0ss a distance.

** data / c0de represented by s0me fr0m 0f electr0magnatic energy (electricity, radi0 waves, lights) transmitted thr0ugh medium (wire, cable, atm0sphere).

Telec0mmunicati0n is a general term f0r a vast array 0f techn0l0gies that send inf0rmati0n 0ver distances. m0bile ph0nes, land lines, satellite ph0nes and v0ice 0ver internel pr0t0c0l (VoIP) are all teleph0ny techn0l0gies -- just 0ne field 0f telec0mmunicati0ns. radi0, televisi0n and netw0rks are a few m0re examples 0f telec0mmunicati0n.

saya baru nak belajau main bl0g

hmm...sebelum nih xpnh p0wn ad bl0g..nih 1st time wt bl0g n bru nk belajau...byk lg yg perlu sy belajau n ketahui tentang bl0g nih..s0,same2 la kte membantu antara satu sama lain yea kwn2.. :D