传送设备

• For a long time , incumbent carriers tended to regard spc exchange , ddn , fr , atm and ip equipment as leading network elements . most often than not , the transmission equipment is only seen as supportive parts for those leading elements
  长期以来，主体电信经营商都认为程控电话交换机、 ddn 、 fr 、 atm 、 ip等设备是作为网络的主体，而传送设备仅认为是这些设备的配套。