One Shot Dial Tone

As part of this project I came up with a one shot dial tone. I was constructing a battery feed circuit for a specific application. He wanted fake dial tone that would go away as soon as any digit was dialed on a rotary phone. This is what I came up with:

Connect "Tone Out" to Talk Circuit

The 42TU-016 has been replaced by a TY-145P from

For information on battery feed circuits click HERE