intelligent pcm120 offers 16 e1 directions and 120 voice channels. all of the 512 time slots can be cross-connected flexibly. the 1u4e1pcm30 offers 4 e1 and 30 channels. all time slots support flexible cross-connect. the ompcm30 mux provides 1 e1 and 1 optical interface as well as 30 voice channels. it can connect directly with 2m interface of the program-controlled switchboards, such as harris, ericsson, siemens and so on. all the cards of the above equipment support hot swap.