The FRM220-4G-3R is a versatile multi-rate fiber transponder that features four SFP slots, which can be configured as a dual-channel 4G 3R multi-rate transponder or in a 1-to-2 port protection mode. It supports a wide range of protocols, including 1G Ethernet, SDH STM-16, OC-24, OC48, Fiber Channel 1/2/4, OBSAI, CPRI, and more. With optical data rates ranging from 1Gbps to 4.25Gbps, it provides flexible transmission capabilities, and when equipped with dedicated CWDM or DWDM wavelengths, it delivers high-performance optical communication. The FRM220-4G-3R can also function as a repeater for long-distance transmission, making it ideal for various network configurations. Additionally, the device supports 1+1 optical line protection with a switching time of less than 50ms, dual-channel operation with different bit rates, and includes useful features such as Loopback Test, SFP DDM information, firmware upgrades, and settings adjustments via DIP switch, console, or NMC. It also integrates Auto Laser Shutdown (ALS) and LFPT functions, while its advanced components ensure low power consumption and reduced heat dissipation compared to previous transponders.