The CWDM OADMs are passive devices that can multiplex/demultiplex or add/drop wavelengths from multiple fibers onto one optical fiber. The OADM connectors are interfaced to the color-matching CWDM GBICs on the equipment side. All the modules are the same size. The CWDM 2-slot chassis allows you to rack mount up to two CWDM OADMs in a single rack unit.
The 4-channel OADM allows you to add/drop four channels (with different wavelengths) into one direction of an optical ring. The other wavelengths are passed through the OADM. Dual fiber is used for both the network and the GBIC connections. The four wavelengths are set to 1470 nm, 1510 nm, 1550 nm, and 1590 nm.