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 dual single-channel OADMs allows you to add/drop two channels of the same wavelength into the two directions of an optical ring. The other wavelengths are passed through the OADM. Dual fiber is used for both the network and the CWDM GBIC connections. The dual single-channel OADMs are color-coded and match the color-coding of the CWDM GBICs.