Midian’s VPU series of inversion voice scramblers protect your voice communications against casual listeners. By mixing the frequency of the voice with an inversion tone in a balanced modulator, sum and difference frequencies are created. A low-pass filter eliminates the sum and the difference is transmitted as “inverted voice”. The “inverted voice” undergoes an identical process on the receiving end that reconstructs the voice.

Midian’s VPU-12A is compatible with Motorola’s VPA, MX-Com’s MXP-1080/1180 series, Transcrypt’s SC20-400 and SC20-401, Selectone’s ST-20 and others.

• Mode indication tones
• Protects against casual listeners
• Scramble/clear mode is selectable
• Small size fits into most radios
• User-programmable for up to 16 codes
• User-programmable to any inversion code between 2100 – 4096 Hz
• Programmable using a Midian programming adapter