QRP side tone generator / code practice oscillator

For low power transmitters with positive keying voltages, Q1/Q2/Q3 form a switching amplifier. When the key is pressed, the collector of Q3 is grounded, turning on Q5 and the activator IC1 and the audio oscillator. The Q4 drives the speakers. As a coded physical oscillator, insert P1, J1 and a button into J2.