单项选择题
A. 15 dB
B. 17 dB
C. 21 dB
D. 26 dB
E. 27 dB
单项选择题 A 2.5 Gb/s （OC-48 or STM-16） optical signal with a dispersion tolerance of 1200 ps/nm goes through fiber with 18ps/nm*km of dispersion. How many 15216-DCU-350 equivalents are needed for enough compensation after traveling 100 km？（）
单项选择题 The ONS 15216 is a 32-channel system. The ONS 15216 OADMs are capable of adding and dropping one， two， or four channels. How are the OADMs provisioned to add and drop specific channels？（）
多项选择题 Whatarethreerelevantdesignconsiderationswhenusingthe15216EDFA？（）
