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).