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CASIO PHONEMATE AND ROCKWELL USHER IN THE 900 MHZ DSS ERA
 A Casio PhoneMate White Paper

Introduction

Like all things technological, the cordless telephone has evolved dramatically in a relatively brief span of time. Yesterdays pricey, static-filled, power-hungry 10-channel 46/49 MHz cordless models spawned more efficient, economical 25-channel cordless units, incorporating features that have enhanced clarity and convenience.

Similarly, when they first hit the market several years ago, cordless phones using the 900 MHz frequency band represented a quantum leap for cordless technology, offering unprecedented range and sound quality. Now, Casio PhoneMate and Rockwell are poised to take 900 MHz to an entirely new level.

The two companies have teamed up to produce state-of-the-art, no compromise cordless phones, built around Rockwells 900 MHz Digital Spread Spectrum (DSS) technology. 900 MHz DSS expands the convenience and mobility of cordless telephone technology with the greatest range, best clarity and highest security on the market, along with optimized talk time. DSS puts about as much distance between it and other 900 MHz options 900 MHz Analog and 900 MHz Digital -- as the original 900 MHz phones put between themselves and the 43/49 MHz class of cordless phones.

This fall, Casio PhoneMate is introducing two new families of 900 MHz DSS cordless products: the flagship TC-950 cordless combo telephone/digital answering machine for the home and small office, and the CP-850, with a Call Waiting Caller ID display that lets you manage incoming calls while on the go.

Both provide high-powered, high-frequency communication between handset and base of up to 4,000 feet under optimum conditions, roughly seven times the range of conventional 25-channel cordless phones. With the high-frequency properties of 900 MHz DSS, the TC-950 and CP-850 both support a high-powered digital signal that enhances clarity better than competing cordless technologies. Rockwell's scrambling of the digital signal also ensures the highest level of security, preventing eavesdropping with scanners or interference from other cordless phones.

This collaborative effort by two market leaders has resulted in a superior solution for consumers, with tangible benefits in areas that matter most in personal and business communications, said Scott Bibaud, Product Manager, Wireless Communications Division, Rockwell Semiconductor Systems. Rockwells 900 MHz DSS technology, integrated with the next-generation Casio PhoneMate cordless offerings like the CP-850 and the TC-950, gives consumers the features they ask for, including range, clarity and security.

Being able to carry on a clear, completely secure conversation -- without interruptions or annoying cross-talk -- means that you dont need to give up range to gain convenience and flexibility, said Stephen Knuth, president, Casio PhoneMate. With its unsurpassed clarity and power, DSS technology redefines the cordless phone in the home and the home office alike. DSS phones sound just like corded phones, but without tying you down.

Cordless Technology Today

10 Channel Cordless

When 46/49 MHz cordless phones were first introduced, consumer response was dramatic -- but the poor voice quality and limited functionality of these first-generation models ultimately did not meet consumer expectations. The majority of analog 46/49 MHz cordless phones in use today can operate on no more than 10 channels. Not surprisingly, these phones are often subject to channel-crowding and cross-channel interference. Electromagnetic radiation in the same frequency band, which can be generated by common household devices such as garage door openers or personal computers, cause jamming and interference. These phones provide a limited transmission range less than 300 feet line-of-sight in most cases, and the signal cannot pass through thick objects such as concrete walls, restricting use of the phone to a small area.

25 Channel Cordless

In early 1995, the FCC added 15 channels (the 43/49 MHz frequency band) to ease overcrowding and interference, opening to cordless phones frequencies previously reserved for the land mobile radio industry. While this more than doubled the likelihood that users would find a clear channel whenever and wherever they called, the 25-channel phone uses the same basic technology as the 10-channel model; neither has built-in protection from interference or any expanded range capability. Voice quality is not markedly better with 25 channel, and the technology makes no special provision for enhanced security.

Inside 900 MHz

The 900 MHz frequency range using the wider 902-928 MHz portion of the spectrum -- represents a growing class of cordless phones; the variations within this class are, however, significant and demonstrable.

Analog 900 MHz

The 900 MHz band provides greater signal strength and shorter wavelengths that travel further than signals in the 43/49 MHz range. The wavelength of a 43/49 MHz transmission measures18 feet while the wavelength of a 900 MHz transmission is just a foot. The shorter 900 MHz transmission bounces off and around objects more efficiently and travels a greater distance than the 43/49 MHz signal.

In theory, this new frequency band should have been capable of producing noise-free sound quality and greater range. Analog 900 MHz phones, however, use the same phone protocol and transmission technology as 43/49 MHz phones, and it soon became apparent that the limitations of analog technology could not be overcome simply by using a different frequency band.

Digital 900 MHz

Digital 900 MHz phones rely on internal circuits that can provide markedly better sound quality and security than analog 900 MHz solutions, which offer no intrinsic security. Unlike analog models, digital 900 MHz cordless phones can transmit a digital security code each time the phone is used. Digital 900 MHz units also digitally encode the users voice before transmission to the base station; voices are scrambled in such a way that only the base station can decipher it. Due to FCC regulations, however, these phones can operate only up to 1 mW output power, limiting their range and the ability of the signal to penetrate thick concrete walls.

Digital 900 MHz Spread Spectrum (DSS)

Spread Spectrum is a frequency utilization technique originally developed for military applications as a secure means of communication unencumbered by natural noise and other signal interference. DSS solutions take advantage of the improved performance of the 900 MHz band and digital transmission. DSS is spread over a wide range of frequencies within the 902-928 MHz band for transmission, enabling the signal to avoid or eliminate interference and noise from other signals. Accordingly, Casio PhoneMates TC-950 and CP-850 models go beyond the functionality of existing cordless phones even other 900 MHz cordless phones -- to provide much longer range, clearer sound quality and higher security.

Not all DSS solutions are alike, however. Spread spectrum signals can be encoded in two ways: direct sequence or frequency hopping. Casio PhoneMate's DSS phones, using Rockwell technology, implement direct sequence encoding to ensure fast and reliable connections. With direct sequence, the information (voice conversation) to be transferred is broken into "chips" or blocks of data and spread over transmitting bandwidth, which reduces the power density of the signal. At the receiving end, the digital "chips" are combined and demodulated.

With direct sequence encoding, channel hopping is smart and occurs automatically during a conversation. Because of this dynamic or smart hopping, users are spared irritating interference and the bother of pressing a channel button (as they must with analog 900 MHz and digital 900 MHz).

This smart hopping technique avoids the errors and interference encountered in frequency hopping systems. The FCC requires frequency hopping-encoded DSS technology to hop quickly through 50 channels, spending only a fraction of a second on each. Direct sequence encoding also filters interference and avoids audio drop-outs better than frequency hopping DSS.

DSS Benefits

Longer Range

900 MHz DSS phones like the TC-950 and CP-850 can operate clearly at an extended distance from the base station up to three to four times further than a typical 900 MHz non-spread spectrum phone and as much as seven or eight times further than a 43/49 MHz phone -- while maintaining continuous talk time. Users are able to move freely around their homes and businesses, or down the street to a neighbors house, without experiencing a degradation in sound quality. DSS phones can transmit up to 1 W of power, while other types of cordless phones, such as 900 MHz analog phones, are limited to 1 mW. This thousand-fold increase in power accounts for the significantly longer range of DSS phones.

Greater Clarity

Because licenses are not required for the 900 MHz band, cordless phones are susceptible to noise from a vast array of unlicensed devices. 900 MHz analog phones are not designed to circumvent interfering signals, but the DSS-based TC-950 and

CP-850 effectively block out unwanted noise.

In spread spectrum modulation, the transmission is dispersed over an extended bandwidth precisely to avoid areas of interference, ensuring clearer conversations. This is where smart channel hopping makes a difference; DSS phones continuously and automatically scan the frequency band for the best channel. Should a jamming signal or significant interference be encountered, the phone performs a smart channel hop to an available clear channel. The conversation continues without interruption.

Highest Security

Because only the receiver has a copy of the pre-assigned spreading code, the spread spectrum technique provides better security than competing solutions. The transmitting signal is dispersed over a large bandwidth, so the signal is more likely to go unnoticed by other systems, which are not tuned to receive it. Casio PhoneMates SecureCom available on both the TC-950 and CP-850 -- enlists 16 million random security codes to protect communication between the handset and the base. The code changes every time the handset is placed in the cradle, making eavesdropping or interception virtually impossible.

Intelligent Power Management

DSS phones include an intelligent power management capability, Rockwells proprietary method of preserving cordless battery life to ensure clear communications at long range. This breakthrough effectively compensates for the power consumptive nature of DSS technology.

In the CP-850 and TC-950, the transmitting power between the handset and base unit automatically adjusts between one, ten and 100 milliamps, depending on the distance between them; power is minimized when the units are relatively near to one another, and boosted as the two are separated and require greater signal strength to maintain clear communications. Underscoring their no compromise feature set, Casio PhoneMates DSS phones offer several hours of continuous talk time and up to seven days standby time.

The Ultimate Cordless Phone Technology

Casio PhoneMate is proud to attach the Connect with Rockwell logo to its new families of 900 MHz DSS cordless telephones. As outlined above, 900 MHz DSS expands the convenience and mobility of cordless telephone technology with greatest range, longest talk time, best clarity and highest security on the market. Casio PhoneMates unique integration of Rockwells core technology has yielded the most powerful DSS solution available one intended to make cordless communication reliable, convenient and secure.

About Casio PhoneMate

Founded in 1968, Casio PhoneMate, Inc. is a leader in the development and design of telecommunications products for home, home/office and small business consumers. The company has consistently introduced industry firsts, including one of the first commercially available telephone answering devices (TAD), the first TAD with integrated cordless telephone, the first implementation of synthesized voice prompting and time/day stamp, the first all-digital TAD, and the first cordless telephone with Call Waiting Caller ID display. Based in Torrance, California, Casio PhoneMate continues to pioneer high-quality, reliable and cost-effective communications solutions. # # #

CASIO PHONEMATE INC.
P.O. Box 2914, Torrance, California 90509-2914
20665 Manhattan Place, Torrance, California 90501
(310) 618-9910 . FAX (310) 212-6316