ots2500, the standard 2. 5g sdh, provides 6×2. 5g
optical directions, 12×622mbit/s
or 12×155. 520mbit/s
optical directions. It also provides fe interface and multiple 100base_t lan
ots622 is designed for stm-1/stm-4 transmission, adopts either interface
of 155. 520mb/s or of 622mb/s, and multiple other interface like e1,e3
and ds3, etc.