Telephone/Door Bell Ring Amplifier 1)Designed for people with hearing loss2) work as wireless door bell and onnected to basic telephone to amplify both ring volumn3)adjustable super-loud ringer (up to 100dB)4)with 3 type ring pattern and tone & volumn adjustable5)Bright visible ringer flashing indicator6)Dual modular phone jack design-eliminates the need for a T adaptor Parameter:1)adaptor:DC9V 500mA2)wireless door bell remote control distance within 30meters