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Off. Bus. tech

A modem (modulator-demodulator ) is a device that modulates  an analog carrier   signal to encodedigital information, and also demodulates such a carrier signal to decode the transmitted information.The goal is to produce a signal that can be transmitted easily and decoded to reproduce the originaldigital data. Modems can be used over any means of transmitting analog signals, from driven diodes toradio.

WiFi and WiMax

Wireless data modems are used in the WiFi and WiMax standards, operating at microwave frequencies.

WiFi is principally used in laptops for Internet connections (wireless access point) and wireless applicationprotocol (WAP).

Mobile modems and routers

Modems which use mobile phone lines (GPRS, UMTS, HSPA, EVDO, WiMax, etc.), are known asCellular Modems. Cellular modems can be embedded inside a laptop or appliance, or they can be

external to it. External cellular modems are datacards and cellular routers.

BROADBAND

ADSL modems, a more recent development, are not limited to the telephone’s voiceband audiofrequencies. Some ADSL modems use coded orthogonal frequency division modulation (DMT)

Cable Modems use a range of frequencies originally intended to carry RF television channels. Multiplecable modems attached to a single cable can use the same frequency band, using a low-level mediaaccess protocol to allow them to work together the same channel.

Fax (short for facsimile, from Latin fac simile, "make similar", i.e. "make a copy") is atelecommunications technology used to transfer copies (facsimiles) of documents, especially usingaffordable devices operating over the telephone network. The word telefax, short for telefacsimile, for"make a copy at a distance", is also used as a synonym. Although fax is not an acronym (as it isabbreviated from facsimile), it is often written as "FAX". The device is also known as a telecopier incertain industries. When sending documents to people at large distances, faxes have a distinctadvantage over postal mail in that the delivery is nearly instantaneous, yet its disadvantages in quality have relegated it to a position beneath email as the prevailing form of electronic documenttransfer except where the legal status of a sent fax and its accompanying sending report are desired.

Importance of fax machineNowadays fax machines are one of the most important office equipment. This fax machine usually sends and receives a document through a telephone line. Using fax machine (facsimile machine) we can

send documents to any point of the world as very convenient and easy. The important feature of the faxmachine is that printing technology. Nearly all the fax machines use plain office paper. Inkjet faxes canusually print, copy and fax the text in color. Laser fax machines are also available usually to printsharper text.

Before buying fax machine we have to see the memory storage capacity. Normally fax machines storeincoming and outgoing pages in the memory. Since business fax machines are used in most businesstransactions, these should be reliable in terms of speed. So another import feature considering is thatspeed. There are so many of variety models coming in Panasonic and Brother printing technologies. Inthe brother fax machine there are much more facilities available is that automatically paper cutting,auto switching system, automatic redialing, on-hook dialing, journal report preparation, 512KB

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Memory (20 pages), key lock system, multi ringing sound, 104 station quick dials, up to 20 pages of memory transmission, fax forwarding, polling, speed dialing and so on.

Different types of brand fax machines are available for sales and service in http://www.lucidtec 

hnocom.net such as brother fax machines, Panasonic fax, brother thermal fax machines, Panasonicthermal fax machines, Panasonic cordless fax machine, laser fax machines, inkjet fax machines andmore. Inkjet fax machines are faster and more expensive than thermal printing, while laser faxmachines are fastest and also most expensive. Canon fax machines are the good choice for small offices.The Canon uses laser technology to send a page in three seconds.

Lucidtechnocom provide complete solutions in LAN, WAN and Microsoft Products and we are intosales and services for all types of fax machines, printers, desktop computers, telephoneinstruments, digital duplicators, telephone systems, matrix system, cordless telephones, copiers,laptops, lenovo notebook computers and for all multifunctional devices.

MODEM is a device that modulates an analog carrier  signal to encode digital  information, and alsodemodulates  such a carrier signal to decode the transmitted information. The goal is to produce asignal that can be transmitted easily and decoded to reproduce the original digital data. Modems can beused over any means of transmitting analog signals, from driven diodes to radio.

ZIP DRIVE

 The Zip drive is a medium-capacity removable disk storage system, introducedby Iomega in late 1994. Originally, Zip disks launched with capacities of only100 MB, but later versions increased this to first 250 MB and then 750 MB.

EARPHONES OR HEADPHONES

Headphones are a pair of small loudspeakers, or less commonly a singlespeaker, with a way of holding them close to a user's ears and a means of connecting them to a signal source such as an audio amplifier, radio or CD player.

 They are also known as earphones, earbuds, stereophones, headsets or,informally cans. In the context of telecommunication, the term headset is used todescribe a combination of headphone and microphone used for two-way communication, for example with a telephone.

Types of headphones

There are many different types of headphone designs, with the listening situation and the needs

of the listener determining what type of headphone will be used. Generally, headphone form

factors can be divided into four separate categories: circumaural ,  supra-aural , earbud , and in-

ear .

Earcup headphones

Earcup or on-ear headphones rest on the exterior of the ear and were the earliest headphone

form designed.

The housing, or earcup, of an earcup headphone will be either open or closed. Openheadphones, sometimes marketed as “open air” headphones, have an open grille on the back of 

the earcup, exposing the driver to the outside and allowing sound waves to propagate away from

the ear freely. This backing type does not isolate the listener from outside sounds; in addition,

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sound through open headphones can be heard by others in the vicinity of the user. They usually

have less distortion due to the lack of earcup resonance. Closed headphones have a sealed

 backing, which attenuates sound waves propagating away from the ear. As a result, listenersaway from the headphones cannot hear the produced sound easily. In addition, sound from

outside is attenuated by the sealed backing, providing a level of isolation to the listener. A sealed

chamber is often claimed to have the negative effect of distorting sound in certain frequencies

due to resonances within the earcup housing, however, bass frequencies are stronger in a sealedchamber headphone design.

Circumaural

Circumaural headphones (sometimes called full size headphones) have circular or ellipsoid

earpads that completely surround the ears. Because these headphones completely surround the

ear, circumaural headphones are often noise-isolating and sealed, but cheaper ones usually arenot. Because the earpads must enclose the ear, circumaural headphones are often larger in size

and tend to weigh more, making them somewhat less portable, but their size also allows for a

larger driver. This type of headphone is commonly used in recording studios and by audio

enthusiasts.

Supra-aural

Supra-aural headphones have pads that sit atop of the ears, rather than around them. They were

commonly bundled with personal stereos during the 1980s. This type of headphone generallytends to be more lightweight.

Earbuds

Circumaural headphones have large pads that surround the

outer ear.A pair of supra-aural headphones

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Earbuds or earphones are headphones of a smaller size that are placed directly outside of the

ear canal, but without fully enveloping it. They are generally inexpensive and are favored for their portability and convenience. However, due to their inability to provide isolation, they are

not capable of delivering the same dynamic range offered by many full-sized headphones and

canalphones for a given volume level. As a result, they are often used at higher volumes in order to drown out noise from the user's surroundings, which increases the risk of hearing-loss.[2]

During the 1990s and 2000s, earbuds became a common type bundled with personal music

devices.

In-ear headphones

Canalphones

Main article: In-ear monitor 

Canalphones (also known as in-ear monitors, or IEMs) are earphones that are inserted directly

into the ear canal. Canalphones offer portability similar to earbuds, and also act as earplugs to

 block out environmental noise. There are two main types of IEMs: universal and custom.Universal canalphones provide one or more stock sleeve size(s) to fit various ear canals, whichare commonly made out of silicone rubber, elastomer , or foam, for noise isolation. Universal

canalphones are typically marketed to casual listeners and are relatively inexpensive, though

some offer very high audio quality.

Custom canalphones are fitted to individuals. Castings of the ear canals are made, usually by an

audiologist. The manufacturer uses the castings to create custom-molded silicone rubber or 

elastomer plugs that provide added comfort and noise isolation. Because of the individualized

labor involved, custom IEMs are more expensive than universal IEMs.

Benefits and limitations

Earbuds or earphones, such as these that ship

with the Apple's iPod, rest in the outer part of 

the ear canal.Canalphones extend into the ear canal, facilitatinggreater dynamic range than earbuds as well as

isolation from outside noise.

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Two Sony MDR-series headphones; one folded for travel

Headphones may be used to prevent other people from hearing the sound either for  privacy or to

 prevent disturbance, as in listening in a public library. They can also provide a level of sound

quality greater than loudspeakers of similar cost. Part of their ability to do so comes from the

lack of any need to perform room correction treatments with headphones. High qualityheadphones can have an extremely flat low-frequency response down to 20 Hz within 3dB.

However, rated frequency response distortion figures do not provide information on what

character the sound reproduced at that frequency will be. Marketed claims such as 'frequencyresponse 4 Hz to 20 kHz' are usually overstatements; the product's response at frequencies lower 

than 20 Hz is typically very small. [3]

Headphones are also useful for  video games that use 3D positional audio processing algorithms,as they allow players to better judge the position of an off-screen sound source (such as thefootsteps of an opponent).

Dangers and volume solutions

Using headphones at a sufficiently high volume level can cause temporary or permanent hearing

impairment or deafness due to an effect called "masking." The headphone volume has tocompete with the background noise, especially in excessively loud places such as subway

stations, aircraft, and large crowds. This leads to the disappearance of the normal pain associated

with higher levels of volumes. Extended periods of the excessively loud volume may bedamaging;[5][6] however, one hearing expert found that "fewer than 5% of users select volume

levels and listen frequently enough to risk hearing loss

 TELEPHONE

 The telephone (from the Greek: τῆλε, tēle, "far" and φωνή,  phōnē, "voice") is atelecommunications device that transmits and receives sound, most commonlythe human voice.

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FAX MACHINES

Fax (short for facsimile, from Latin fac simile, "make similar", i.e. "make a copy")is a telecommunications technology used to transfer copies (facsimiles) of documents, especially using affordable devices operating over the telephone network. The word telefax, short for telefacsimile, for "make a copy at adistance", is also used as a synonym. Although fax  is not an acronym (as it isabbreviated from facsimile), it is often written as “FAX”. The device is also knownas a telecopier in certain industries.

ADVANTAGES & DISADVANTAGES

BENEFITS

HOW TO USE

PRINTER - is a peripheral which produces a hard copy(permanent readable text and or graphics) of documentsstored in electronic from usually on physical print media such as paper or transparencies.

KINDS OF PRINTER  

* Dot Matrix- forms characters on a page according to patterns set for each character.

* Laser Printer- laser technology to create an image that is transferred to a carrier, such as paper orfilm.

* Ink Jet- technology that creates an image by spraying tiny jets of ink, has come a long way.

* Color or Monochrome- still dominates the market, it make up special presentation, it may even benecessary.