GENERAL DESCRIPTION

The PCD4440T is a silicon gate CMOS integrated circuit intended to be used in cordless telephony, radio, and line telecommunications products utilizing a microcontroller for the control functions. The purpose of the device is to prevent unauthorized ‘listening-in’ on conversations. A major application is protection of the vulnerable radio link between a CT0 type cordless handset and its base unit. Analog scrambling/descrambling is based on the split frequency method realized in a sophisticated switched-capacitor technology. The PCD4440T is compatible with most microcontrollers and communicates via a two line bidirectional I2C-bus.

FEATURES

? Scrambler or descrambler function

? Scrambling in frequency domain

? Selectable split frequency (up to 10 selections per second)

? Telephony-band filtering included

? No increase in bandwidth

? No external components required

? Small signal delay

? Insensitive to distortion and group delay of transmission channel

? Control via serial I2C-bus

? Low transfer loss of speech

? Mute option

? Transparent mode

? High signal input impedance

? Low signal output impedance

? Low power consumption.

APPLICATIONS

? Cordless telephones

? Security telephones

? Portable phones

? Private Mobile Radio (PMR).