The series incorporates a robust heat dissipation design for PHY chips and optical modules, ensuring long-term stability and reliability. Whether you are looking for the smallest handheld 100G bit error rate tester in the world for your field job, or perhaps your needs take you into the lab, VIAVI has you covered with our accurate and easy-to-use BERT equipment for any use case. The T-BERD/MTS-5800-100G handheld network tester is the. A Bit Error Ratio Tester (BERT), is an electronic device that tests how error-free data transmission occurs in a digital circuit. OPTELLENT's test and measurement equipment are designed to offer unprecedented low-cost of ownership and ease of use. In simple terms: it tells you how “clean” or “error-free” a digital communication channel is.