Hands-Free

Cell Phone Speaker/Microphone

Quick & Easy to install ! Patented technology eliminates feedback and echo for comfortable hands-free communication with cellphone. For All Cell Phones Using a StandardRound-Pin 2.5mm Jack. Adapters needed for some phone models. Compatible with CDMA, TDMA and GSM Phones.

Features

Allows parties on both sides of the conversation to talk and listen at once.

Battery-powered. The only cable needed is the one from your mobile phone to the hands-free unit(included)

Uses a special noise suppression circuit so that surrounding noise is nearly eliminated, even at highway speeds.

Uses an energy-saving circuit to turn itself on and off automatically. Average battery life with normal use is about 6 months Energy-saving circuit turns off the unit after 2 minutes of silence from other party.

DH-500 Tips for Installation

Patent in DH-500

The patent relates to an electronic circuit that realizes the following function:

The circuit is connected to the output of a microphone and amplifies human voices selectively. The circuit recognizes human voices from signals falling within a certain range of frequencies. The output of the selecting circuit controls the degree of amplification of the microphone output

This circuit has been burnt into a silicon in the form of an analogue chip. The design belongs to Pan Communications, Inc., while the chip was completed by Hitachi engineers. The chip is currently supplied by Renesas, a joint venture between Hitachi and Mitsubishi Electric.