2.4GHz cordless phones: Broad user base buoys established line

Competition from other telecoms products and services is cause for little concern, but makers believe industry still sustainable.

China suppliers of cordless phones have seen export volume drop continuously since 2005. This is due to the increasing use of VoIP and mobile phones worldwide, and relatively slow demand for fixed phone lines or landlines.

The decline is expected to continue. Suppliers, however, said there is a large and established user base of public switched telephone networks that can sustain the product line for at least 5 more years. They also believe that the telecom market is big enough for cordless phones to thrive together with their more popular counterparts.

In 2008, China suppliers produced approximately 60 million cordless phones, accounting for more than 90 percent of global output.

Generally, China-made cordless phones use the 900MHz and 1.9, 2.4, and 5.8GHz bands. Some models with lower technology utilize the 27MHz and 43 to 50MHz bands.

Nearly all new 900MHz designs are inexpensive bare-bones analog models. Digital features such as direct-sequence spread spectrum and frequency-hopping spread spectrum that minimize signal interference are usually integrated in units using the higher frequencies.

In recent years, the 900MHz and 2.4GHz bands have been used by other devices, including baby monitors and microwave ovens, and Bluetooth-and Wi-Fi-enabled products. This has caused occasional signal interference, resulting in inefficient operation, especially for gadgets that fall under the telecommunications category.

Most countries, however, have allocated the 1.9GHz frequency for voice telecommunications. The band is reserved for the DECT standard that avoids interference issues increasingly seen in the unlicensed 900MHz, and 2.4 and 5.8GHz frequencies.

To extend battery life, some models use the 5.8GHz band when transmitting from the base station to the phone. A lower frequency, usually 2.4GHz or 900MHz, is adopted for signals transmitted from the phone to the base station.
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