Phone Features | Voice Communications

In addition to the basic issues of portability, power, durability, and reliability that are certainly key decision points when selecting a cellular telephone, it is often additional features and options that distinguish one unit from another. The cost of the unit is certainly a major factor for many purchasers, and identical units can vary greatly in cost, especially when bundled with cellular network service commitments. On a straight purchase basis, cellular telephone list prices can range from under $100 to $800 and above. Competition has fostered aggressive discounting, and additionally, service providers offer telephones at discount or at no cost, in exchange for a commitment to utilize their network service over a specified period of time.

Call handling features

There are many call handling features that are offered by wireless service providers that facilitate ease of use or offer added value. Some of these features are standard in that they are supported throughout the entire range of handsets and usually do not involve extra charges. Other call handling features require that the subscriber have the right kind of handset to access them. Many value-added features are considered options and may entail extra charges. However, due to increasing competition, some value-added features that were once considered extra-cost options are now being offered free to attract new customers. This situation is constantly changing; first-time subscribers should compare service providers in their area for the latest developments.

Among the basic call handling features offered by many wireless service providers at no extra charge are:

• Call hold permits the phone user to momentarily put an existing call on hold while he or she attends to another task.
• Call waiting provides an indication of an incoming call while the user is busy with another call.
• Call forwarding allows incoming calls to be forwarded to any designated wireless or wireline phone.
• Call alert provides audio and/or visual indication of an attempted call.
• Silent call alert includes visual or vibrating notification in lieu of an audible signal. This can be particularly useful in locations where the sound of a ringing phone would constitute an annoyance.
• Single-button callback allows the subscriber, at a convenient time, to press a single button to call back a person who left a call alert.
• Do not disturb enables a subscriber who is busy with a conference call to set the handset to disable the call alert feature. This prevents the subscriber from becoming distracted by call attempts.
• Last number redial allows the phone user to redial the last number called with the push of a button instead of having to redial all the digits.
• Selective call restriction permits the user to program the phone to disallow calls to specified country codes, area codes, exchanges, or telephone numbers. However, calls will still go through to emergency numbers.
• Phone list stores speed dial numbers. Depending on the memory capacity of the particular handset, 100 or more speed dial numbers may be stored.
• Character mapping allows easy recall of important phone numbers. This feature allows the actual names of individuals to be used instead of their telephone numbers. As many as 11 characters may be used.
• Extended telephone numbers allows up to 20 digits to be entered as part of the telephone number to include an extension or other information, as well as an 11-digit long distance number.

Convenience features

Today's wireless handsets are equipped with a number of features that make them more convenient to use. Hands-free operation, for example, is especially useful for mobile users in terms of safety as well as convenience. This is equivalent to a speakerphone function on a conventional telephone. In its basic configuration, it allows the user to converse without holding the handset after the call has been established.

A remote earphone/microphone combination cable is available that can be plugged into some phones. This allows the user hands-free operation and provides confidentiality for at least the received side of the conversation. A portable phone can be attached to the user's belt, and the earphone/microphone cable plugs into the telephone.

One of the newest innovations in hands-free operation is the inclusion of a proximity detector located next to the earpiece in the handset. The proximity detector emits an infrared beam and senses a reflection when the handset is brought close to a person's ear. A digital signal processor (DSP) equalizer then automatically lowers both the receive and transmit volumes to levels that ensure the privacy of the call. The transition is so smooth that the listener on the other end of the call will not notice any difference in sound quality or sense that a switchover between handset and hands-free operation has taken place.

To improve the audio quality of hands-free communication, the ported loudspeaker has been developed to eliminate the "canned" sound most people experience with hands-free operation. The ported loudspeaker, normally found in home stereo systems, has a tube that penetrates the sealed mounting enclosure. The tube is designed so that the air column inside resonates to amplify lower frequencies, providing a better bass response. The ported loudspeaker has now been adapted for use as a receiver in compact cellular phones for both handset and hands-free operation. Frequency shaping is dynamically controlled in response to the mode of operation with the result that sound quality remains the same.

A related convenience feature is voice activated dialing, which combines speed dialing with voice recognition technology. It permits users to dial a phone number with one or two buttons and speak into the handset or vizor-mounted system instead of punching in the full telephone number on the keypad. Since users can assign names to phone numbers, they do not even have to remember each person's phone number or fumble around looking for them in an address book.

Speech recognition technology enables the user to program important phone numbers into the phone and equate each number with a spoken command. For example, by pressing two digits and using voice commands such as "Call office" or "Call attorney," the cellular phone will initiate dialing and place the call. Such systems also accept number and command imprints in different languages. Users can even create a directory of personalized listings. Depending on the system used, 20 or more listings can be stored in the cell phone for voice activated dialing.

In addition to stored commands, users can also voice-dial a number by saying "Dial" and stating the number. Access codes allow customers to activate automated systems, such as voice mail back at the office, without pressing any additional keys once the automated system answers.

Handset features

Handsets are becoming increasing sophisticated. Among the areas undergoing rapid technological advancement is the handset display. Traditionally, wireless telephone displays have employed relatively low-contrast passive matrix technology to minimize costs and power consumption. However, as wireless services are increasingly used for electronic transactions (such as home banking and shopping), short message services, Internet access, image transfer, and possibly full-motion video applications, high-performance passive matrix displays are being added to wireless handsets.

Among the technologies being used to improve handset displays is film super-twisted nematic (FSTN), a polymer optical compensation film that is laminated to the viewing screen to sharpen the contrast and deliver neutral black-white renditions. The film corrects for out-of-phase wavelengths that typically arise on systems using conventional STN technology.

Another technology being pursued by some vendors is a new class of low-cost color liquid crystal display (LCD). For many emerging telephony applications, color can provide additional visual indications to help users quickly navigate their way through increasing amounts of screen-based information. Different colors, for example, can be used to partition or layer information into categories for quicker identification and access. Color can be employed to highlight particular information on a crowded display screen, or to emphasize warning signals and important events, such as low battery power or signal strength.

For such applications as portable wireless telephony, where power consumption and backlighting requirements impose severe limitations, the use of reflective color technology is being explored as an alternative to existing color LCDs. This relatively new technology uses a special liquid crystal material that enables color to be determined simply through applied voltage—the same way that lower-cost LCD monochrome displays are controlled. Reflective color technology eliminates the color filters required in traditional color LCDs, which subdivide each pixel into three subpixels—red, green, and blue—and use three filters to vary the intensity of these primary colors in the color mix. In reflective color systems, each pixel generates its own color in response to the applied voltage.

Unlike traditional color LCDs, the reflective color system requires little additional power, no extra backlighting, and costs only about 10 percent more than LCD monochrome displays. Although the technology today provides a limited number of colors—compared to the 256 in a standard notebook computer display—advances in display technology will soon push the number of available colors much higher. Even with a restricted color palette, reflective color is adequate for use in the graphics-and-text interface appropriate for most telephony applications.

Touchscreen technology is another area being improved for such applications as e-mail and messaging. With this technology, users can directly enter, select, or highlight data on a touch-sensitive screen by pressing on-screen buttons next to the displayed information or by writing with a stylus (pen) instead of having to use the alphanumeric keypad. A stylus could be paired with handwriting recognition, for example, to let users bypass the keypad when entering names and numbers into a directory.

As screen phones are increasingly used in homes or other environments where lighting may be dim or nonexistent, vendors are using high-efficiency light-emitting diodes (LEDs) and lightpiping to backlight LCDs and illuminate buttons and status indicators. Rather than locate the LEDs directly behind the LCD, vendors such as Nortel are placing an LED array to one side of the LCD and employing a lightguide in back of the screen to evenly distribute illumination over the entire display. A pattern of dots is printed on the flat plastic lightguide to diffuse the light and eliminate hot spots of illumination typical in conventional handsets. This solution reduces the number of LEDs in a normal phone display from 100 or more to just eight, which greatly reduces both the power demands and the cost of the handsets.

A number of other features inherent to the handset itself make various tasks easier to perform. Among these features are:

• Call timer provides the subscriber with information on the duration of a call. Some telephones can also maintain a running total of airtime for all calls. These features make it easier for users to keep track of call charges.
• Visual status displays convey a variety of information such as number dialed, state of battery charge, call duration, signal strength, roaming, and operational errors.
• Keypad lock enables the subscriber to prevent unauthorized calls by password protecting the keypad.

With the increased use of cellular telephones for personal use, the choice of color and styling is playing a greater role in handset selection, particularly for fashion-conscious young people. For example, some Motorola handsets come in such diverse colors as sunstreak (yellow), dark spruce, eggplant, teal, raspberry, regatta blue, temptation teal, and cranberry. Not to be outdone, Nokia's 1998 color palette includes high-gloss and brushed metallic finishes such as midnight black, hunter green, turbo red, pewter, antique bronze, and signal glow, to name a few.