5.8GHz does not necessarily mean high costs and bad performance!

Progression from 2.4GHz to 5.8GHz

The race is on in North America to provide the market with high quality digital cordless phones. In the last couple of years we have seen a lot of 2.4GHz digital cordless phones hit the market. The quality, range, and feature set has been very well accepted in North America and many companies are now involved in this market. With the rapid deployment of home networking in the form of 802.11b/g WLAN systems, Bluetooth, and other proprietary 2.4GHz systems, the open 2.4GHz ISM band is starting to show early signs of congestion. For a pure data system, the congestion or noise is not a major issue. To the user, the data speed is simply slightly reduced as data networking is data packet based and therefore the noise is normally not noticed at all by the user.

Voice quality problems in 2.4GHz

For voice it is a completely different matter, as the voice data is streamed. To some degree the cordless voice protocol can handle noise in the 2.4GHz frequency band but if the noise is above a certain level the stream cannot be maintained and the user will hear this as acoustic cracks with a resulting reduction in quality. With new data/voice combo products this is an even more serious problem, as integrating voice and data into one box will, if both use 2.4GHz technology, make it very difficult for the designer to make a good, robust system of the range and performance expected of a standard 2.4GHz product. For this reason and of course to differentiate the product portfolio, a number of companies have already introduced 5.8GHz cordless telephones in the North American market.

Our 5.8GHz platform is based on our DECT and 2.4GHz technology platform

In 2002 when the first 5.8GHz digital phones appeared on the market, RTX started the development of a 5.8GHz telephone based on the same platform as the one we use for DECT and 2.4GHz. The overall intention was to supplement our platform with 5.8GHz while maintaining our stable software platform. This of course also has the advantage for RTX and RTX customers that the development of a 5.8GHz telephone can make use of the extensive library of features and functions we have built up and tested already.

RTX uses 5.8GHz for both up and down link

When we say a 5.8GHz solution we really mean a 5.8GHz solution! This means that the RTX solution is a true 5.8GHz telephone using 5.8GHz for both the up and the down link. From a hardware perspective we also focused on the Bill of Material and with components already available today.

• The base band processor used in our prototype is the SC14428 from National Semiconductor (NSC).

• The RF is based on the new CMOS DECT LMX4168 RF transceiver also from NSC.