Calytrix's CNR-Sidetone electronic "audio realism" device has been enhanced with a Microphone Boost circuit. This user-switchable addition lets CNR-Sidetone be used with microphones having a high or low level output signal. An example "low output" mic is the military standard H-250 (shown).

CNR-Sidetone's front panel uses 3.5mm jacks for audio out to headphones and audio in from the user's microphone.  3.5mm jacks are very common connectors for audio, allowing CNR-Sidetone to be used with low cost consumer-style headsets.  Because military-style headsets and handsets, like the H-250, use the ruggedized U-229 connector, Calytrix offers an adapter with 3.5mm plugs on one end and  a mating connector for the U-229 on the other end.