Type of screens

LCD
Liquid Crystal Device (or Display). Liquid Crystals are long thin, rod-like molecules that have physical properties that depend on direction, but can flow like a liquid. Application of an electric field causes the liquid crystal to align in the direction of the applied field. Contact with an appropriate surface also aligns the molecules in some predetermined direction. A conventional LCD operates by ensuring that the optical appearance of the surface aligned liquid crystal is different to that of the field aligned state. For example, one state may be bright and the other dark, thereby giving optical contrast.

OLED
Organic Light Emitting Diodes. There has been much interest in the emergence of OLEDs and Light Emitting Polymers (LEPs) that perform in a similar fashion to the LEDs used in early digital wristwatches but with lower power consumption and easier fabrication methods.
PLED Polymer Light Emitting Diode is one type of OLED based on polymeric organics

STN
Supertwist Nematic is used in most mobile phones and PDAs today. A type of LCD display technology. STN uses less power and is less costly than TFT technology, but at the expense of image quality and response time.

TFD
Thin Film Diode. A type of LCD display technology. TFD technology combines the excellent image quility and fast response times of TFT, with the low power consumption and low cost of STN.

TFT
Thin-Film Transistors are used to generate the appropriate signal at each pixel in Active Matrix Displays.

ZBD
Zenithal Bistable Device is a new type of Passive Matrix LCD that has an appearance at least equivalent to Active Matrix LCDs, combined with substantially lower operating power and image storage. It uses a grating surface capable of defining two or more different stable states in which the liquid crystal molecules have different orientations in the plane normal to the cell (the zenithal plane).


Screen quality factors

Active/Passive
A display is said to be passive when applying appropriate signals to the edges of the panel can create the image.
For example, the STN type of display used in most PDAs is passive matrix: voltages are applied to the rows and the columns so that a high voltage appears at some pixels and a low voltage appears at others.
The voltage difference is related to the number of lines addressed, so display complexity of conventional Passive Matrix modes is limited. One solution is to use Active Matrix, where a thin-film transistor (TFT) is fabricated directly onto the glass substrate behind each pixel


Color Quality
1 bit - Black and white
4 bit - 16 colors
8 bit - 256 colors
12 bit - 4096 colors
16 bit - 65 536 colors
18 bit - 262144 colors
24 bit - 16 777 216 colors
32 bit - 4 294 967 296 colors
a simple counting som can get you to the number: 2^bit. There is no reason to enhance the 32bit screen due to the Human eye that can see only a diversion of 2-3 million colors.


Resolution

When working with screen resolution we talk about pixels. Pixels are simply blocks of color (R/G/B) arranged in a grid. The grid makes up whatever image you are looking at.
A screen and an image can both be measured in pixels. We use the term ppi or Pixels Per Inch. This specifies how many pixels represent a linear inch of an image or monitor screen.
With mobile phones (due to the small amount) we don't use ppi but just say the amount of pixels on the horizontal line and the line down. You get something like 160x128

Size

How big the visable display is measured in cm or inch.

Reaction time

If pixels change intensity/color at the same time it takes some time to change the light intensity. On high-end TFT-screens this reaction time is between 20 milliseconds and 40 milliseconds. On the cheaper models the reaction time is 50 milliseconds or even more (like STN). If the reaction time is greater then 40 milliseconds the display in fast action scenes will be slowed.

Contrast/Brightness
When the flatpanel has to show a black background the pixels don't pass light but in practice it never works 100%. Because that the black images are more very dark gray. A TFT get a 300:1 rate wile a CRT gets 500:1 contrast rate.

Brightness or how much light is emited or cd/mІ. the backlight is most reponsable for STN screens.

Source: Kristof.Vanriet from the mobile-review.com forums

Connection technologies

Radio frequency Bands;

The RF Spectum extends from 3kHz to 300GHz. The most important are those (for this subject)
these bands are unlicend:

The 2.4 - 2.5 GHz for IEEE 802.11b, Bluetooth and Home Cordless phones and microwave ovens
And the 5Ghz for IEEE 802.11.

Bluetooth
A wireless interconnect technology standard, designed to replace the many cables we need to connect devices. This technology will let you walk into a room and communicate with your PC or other Bluetooth-compliant devices. The Bluetooth specification was created in February 1998 by a consortium comprising inventive minds from Ericsson, IBM, Intel, Nokia and Toshiba
The odd name is derived from an aggressive Viking king so fond of blueberries that they stained his teeth.
Bluetooth is a good, low-power data/voice transmission standard that will be a real boon for certain applications. Imagine a cell phone or pager that automatically transfers to vibrate mode when you enter a restaurant or theater. Or a laptop and GPS (global positioning system) that automatically feed a display in your car for directions. One of Bluetooth's design strengths is its low cost. The Bluetooth SIG says integrating this technology should add only $5 to the cost of a unit.
Bluetooth operates in the 2.4 Ghz band and got 3 power classes:
Class 1: 100 milliwatt, 20 dBm, 1Mbs, 100 Meters
Class 2: 2.5 milliwatt, 4 dBm, 1Mbs, 10 Meters
Class 3: 1 milliwatt, 0 dBm, 1Mbs, 10 Meters
The speed of 1Mbs and the distances are under optimal conditions, normaly a speed of 700-800 Kbs is more likely
Bluetooth traffic has 2 types; Voice and data. Voice traffic has a much lower tolerance for interference than does data traffic.

The security of the bluetooth network is less than wonderful. You have 3 types;
Level 1: No security.
Level 2: Service-level-enforced security. Security is established after channel negotiation.
Level 3: Link-level-enforced security
The second level is the most used.
and for those who wanna know;
there are 5 stages of activity of a bluetooth network: standby, inquire, page, connect and park/hold.
Standby is a radio waiting to join a piconet (PAN).
Inquire is a radio seeking other radios to connect.
Page is a master radio asking to connect to a specific radio.
Connect is a radio active on a piconet as a master, slave or simultaneous.
Park/hold is a low-power connected state.

IEEE 802.11a, b, g,... or WIFI
Wifi is much more faster than Bluetooth with speeds up to 11-54 Mbs and a operation range of 400 meters.
There are some basic differences between. Bluetooth is designed for connecting 2 or more devices for sharing data and voice and Wifi is more designed to connect a whole network.

the standards from a to g are updates on speed and security;
802.11a
An IEEE specification for wireless networking that operates in the 5 GHz frequency range (5.725 GHz to 5.850 GHz) with a maximum 54 Mbps data transfer rate. The 5 GHz frequency band is not as crowded as the 2.4 GHz frequency, because the 802.11a specification offers more radio channels than the 802.11b. These additional channels can help avoid radio and microwave interference.
802.11b
International standard for wireless networking that operates in the 2.4 GHz frequency range (2.4 GHz to 2.4835 GHz) and provides a throughput of up to 11 Mbps. This is a very commonly used frequency. Microwave ovens, cordless phones, medical and scientific equipment, as well as Bluetooth devices, all work within the 2.4 GHz frequency band.
802.11g
Similar to 802.11b, but this standard provides a throughput of up to 54 Mbps. It also operates in the 2.4 GHz frequency band but uses a different radio technology in order to boost overall bandwidth.

WIMAX or Super WIFI
Wimax is a technologie that allows to provide internetconnection of a hole city. It has a speed of 70Mbs and it can carry signals over distances of 50Km. This a direct threat to the 3G network althow it can't carry voice, it can be used for VOIP (voice over IP). This technologie is just in developing fase and will be available at the beginning of 2005.

IR of Infrared
Infrared uses the invisable red light to communicate with devices. it need a staight line up between transmitter and reciever within 1 meter. The speed can go up to 4Mbs (high speed infrared connection) but normaly with mobile phones the speed is not more then 115Kbs.

The wireless Data-Protocols

GSM and cdmaOne A are both 2G or second generation cellular system for carring voice and data, bot work on the same basics. If you wanna know more about this visit http://www.gsmworld.com in the history part.

TDMA or Time Division Multiple Access: a technology for delivering digital wireless service using time-division multiplexing. TDMA works by dividing a radio frequency into unique time slots and then allocating slots to different users (2 each). In this way, a single frequency can support multiple, simultaneous data channels. Mostly used in the Americas.

PDC is the same as TDMA but used as GSM cellular system.

W-CDMA and cdma2000 are both 3G or third generation of mobile communication. the improvements between the 2G and 3G are better voice quality and a bigger bandwith, IP traffic, greater capacity and improved spectrum and better roaming

UMTS or Universal Telecommuncation System is commonly used alongside the term 3G in Europe. This can be confusing however, as UMTS refers to a specific implementation of WCDMA within the 2.1GHz band which is the frequency that is made available for 3G in Europe and other parts of the world. It is an implementation of 3G

the follow up of technologies are going to be
- cdmaOne -> cdma2000 1x -> cdma2000 1x EV-DO or EV-DV
- TDMA to cdma2000 1x or to GSM (most will use GSM)
- GSM -> GPRS -> EDGE -> W-CDMA

So you are going to have 2 systems CDMA2000 and WCDMA

DATA for GSM

WAP or Wireless Application Protocol: a protocol to discribe how data is send and transmitted to a mobile phone.

GPRS or General Packed Radio Service: is a packet based technology for data transfer over an IP-based network and used as an enhancement for GSM networks, The speed of a GPRS capable device depends on how many timeslots (1 to 8, shared by active users) within a TDMA frame are used. Up and downlink are treated separately and various radio channel coding schemes allow bitrates from 9 to over 171.2 kbit/s (if device were to use all 8 channels without error correction) per user

HSCSD or High Speed Curcuit Switched Data: is an enhancement of current GSM networks allowing users to send and receive data with higher speeds. This is achieved by increasing the speed of one channel as well as giving the option of using several channels at the same time, which results in speeds close to 60 Kbps. This makes HSCSD particularly interesting to people who want to access the Internet at higher speeds than current GSM phones.

EDGE or Enhanced Data rates for Global Evolution (EGPRS): EDGE is being developed to be the basis for a 3G wireless standard which can be used by TDMA and GSM operators. It works with a new modulation technique which allows for better usage of existing frequencies. This means that EDGE can be deployed on existing GSM networks. EDGE enables data transfer speeds of up to 384 kilobits per second. This translates to 48 Kbps per timeslot enabling three times the data speeds of GPRS.

WCDMA or Wideband Code Division Multiple Access is a 3G technology used in UMTS. Data transfer speeds go up to 2 Mbps, and due to the efficient use of the radio spectrum, a wealth of different services can be accessed simultaneously including circuit and packet services with varying bandwidths. WCDMA data transfer speeds will go up to 10.8 Mbps.

HSDPA or 3.5G, not much is know about it, but this will be the GPRS of a 3G network, in run up to the 4G network, but this is future talk, not before 2010...



DATA for CDMA2000

cdma2000 is an IMT-2000 standard and included in the evolution part from cdmaOne.

cdma2000 1x will double the voice capacity and allow up to packet-based data transfer speeds of up to 307 Kbps.

cdma2000 1xEV, the next step, will allow for up to 2.4 Mbps data transfer rates (1xEV-DO, data only) and 4.8 Mbps in phase 2 (1xEV-DV, data and voice).

WML or Wireless Markup Language: a markup language based on XML. it a browser context how text and images will be showed on a small screen device.
XHTML is a more advanced Markup Language.

Push to Talk
A one-way communication function in a mobile phone which lets one user at a time talk to another user or a selected user group. Push to talk is activated by pressing the push to talk key or equivalent on the phone. In a user group, the turns to speak are requested by pressing the push to talk key and granted on a first come, first served basis.

Push to Talk over cellular
A service that provides direct one-to-one and one-to-many voice communication in the cellular network. Calls can be started both to individuals and to talk groups with just the push of a key. Call connection is almost instantaneous and the receiver does not have to answer the call. A specifically PoC-enabled terminal is needed for the service.

Source: Kristof.Vanriet from the mobile-review.com forums

Es sieht so aus als ob sich Apple die ganze geschichte mit den iMacs noch mal anders überlegt hat.
Wenn man den neusten Gerüchten traut sieht es so aus als ob Apple im Januar eine neue Generation iMacs vorstellen wird, die unter der Preismarke von 500$ verkauft werden.
Egal ob dies nun wirklich der Fall sein wird oder nicht, das ganze würde Sinn machen. Denn diese neuen iMacs würden den Gerüchten nach ohne Bildschirm verkauft werden.
Vieleicht ist das die Antwort auf das Bedürfniss der vielen iPod Benützer die behaupten sie würden einen Mac kaufen, wenn diese nicht so teuer wären...

We'll see!

It looks like the guys from B&O (Bang & Olufsen) thought it would be nice to create a mp3 player made of stainless steel but without a display nor any internal memory!
The "BeoSound 2" is the first mp3 player made by B&O and you won't probably be able to buy it at IKEA.
The price is set at 460$. Memory not included. You'll have to buy your own SD-Memory for this device.