291 Optical Encoder Tusonix / CTS 291 Optical Encoder is a high-performance featuring long life, precise digital signal output, compact size, and flexible construction. This encoder is one of the smallest optical encoders available with a 12mm profile. Tusonix / CTS 291 offers 6 and 8PPR resolution, as well as 3M life cycles (with no detents), and 1M cycles (with detents - up to 64PPR available). Lower power consumption is provided with 5VDC or 3.3VDC operating voltage.