A Bit Error Ratio Tester (BERT), is an electronic device that tests how error-free data transmission occurs in a digital circuit. This tester is the industry's smallest 10G handheld instrument and supports testing throughout the entire service. Its portability and simplicity make it an ideal replacement for aging test equipment. Able to maintain pattern sync beyond 4. OPTELLENT's test and measurement equipment are designed to offer unprecedented low-cost of ownership and ease of use. It can be affected by a variety of factors, including signal to noise, distortion, and jitter, so accurate BER measurement helps to pinpoint problems.