Populated on the VoiceBox Shield are the 18-DIP SpeakJet IC and a two stage audio amplifier with a potentiometer to set the gain. You can connect a speaker directly to the 'SPK+/-' pins, and get your Arduino-bot talking with very minimal work!
You can control the SpeakJet through either its serial line, or the eight event input lines which are connected to digital pins 5-12. A 3-way jumper allows you to connect either the software (D2) or hardware (D1) TX pin of the Arduino to the SpeakJet's serial input.
Also included on the shield are a 13x7 grid of 0.1" pitch through-holes for prototyping, the Arduino's reset button. Headers are not included.