I haven't come to 9CBS for a long time. I have been engage in CPOS these days. It is very wide in the telecommunications industry. It is currently SMT-1,155m. It can be divided into 63 E1 (2.048m), or can be subdivided, each E1 can be divided into 32 time slots, each 64K. At present, my country has adopted 373 packaging.
I have learned this thing when I read college, but I didn't learn well. I didn't expect it to make this thing again after graduation. It seems that many things in college are still very useful.