The product is a high speed transistor optocoupler produced by Fairchild Semiconductor Corporation with the model 6N135, 6N136, HCPL-2503, HCPL-4502, HCPL-2530, and HCPL-2531. It has the characteristics of high speed, high common mode rejection ratio, dual channel, high working voltage, guaranteed photoelectric ratio, etc. It is widely used in line receivers, pulse transformer replacement, output interface to CMOS-LSTTL-TTL, wide bandwidth analog coupling and other occasions.