A chirped RZ-AMI optical transmitter includes a first logic gate for receiving a first signal obtained by pre-coding binary data and a second signal having a waveform obtained by inverting and delaying the first signal, and outputting a third signal obtained by logically operating on the first and second signals. A small degree of intentional misalignment of the waveguide will create different levels of optical attenuation. Other steps include selecting at least one choice from the presented list, and granting system access if the selected choice matches the preset choice. A drill or other device to be positioned is mounted on a Y-axis carriage that is slidably connected to the X-axis carriage. The output of each of the voice recognition units is then merged on a time basis to produce a textual transcription of the entire telecommunication conference call. Generating a result signal in each evaluation channel.