多项选择题 What are two important considerations when using 2- or 4-channel 15216 OADMs?（） (Choose two.)

单项选择题 Click the Exhibit button. Given the following parameters: transmitter output (min): -2 dBm receiver input (min): -28 dBm 15216 Mux and Demux loss: 4.5 dB 16 channels maximum In which sites shown in the exhibit could the 15216 EDFAs be placed to minimize the number of EDFAs needed?（）

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?（）