Introduction

Date: 2015-10-07; view: 474.

Part I (49.1 – 49.3.1)

Cordless telephone products first appeared as a low cost option for the home in North America during the late 1970's. Technically it was a radio extension telephone that operated at low power, to conserve operating time between battery charges, and frequencies of 1.7 MHz (base to handset) and 49MHz. (handset to base). The chosen technology was analogue frequency modulation which re­sulted in prices around $ 100 for a residential unit. Although range around the home was limited, typically covering an apartment or a house and gardens, the combination of low cost and freedom of use made the idea an instant success; they sold in their millions and still do.

The success was exported to Europe by way of illegal imports into the UK, France, Germany, Holland, etc. These imports infringed local telecommunications law and practice. In the UK, for example, the frequencies chosen for North American were allocated to ma­ritime and the then broadcast television service. Furthermore their transmission characteristics gave unsatisfactory speech perfor­mance when they were connected to European public telecommuni­cations networks. Nevertheless the quantity of illegal imports demonstrated that a market existed for such a product and conse­quently the European PTT's reacted by adopting appropriate stand­ards for Europe. From this beginning the present cordless market is now on the verge of making a significant breakthrough as a natural telephone terminal apparatus in both the home, office and manufac­turing environments.