Music-On-Hold Box Electronic Circuit - CircuitsArchive

From CircuitsArchive
Jump to: navigation, search


U1, an LS3404 melody chip is activated when "hold" S1 is pressed, which causes SCR1 to conduct and hold the telephone line via T1, R1, and LED1. The voltage across R1 and LED1 is used to activate the melody chip. Q1 and Q2 form a restart circuit to keep the melody chip going during hold.


Cir telephone 005.gif



Personal tools
Follow CircuitsArchive on Twitter
AllPinouts is owned by Tecnick.com LTD, the content is available under GFDL.