The Cisco CWDM OADMs are passive devices that provide the ability to multiplex and demultiplex, or add and drop wavelengths from multiple fibers onto one fiber. The OADM connectors are interfaced to the color-matching Cisco CWDM GBICs or Cisco CWDM SFPs on the equipment side. All modules are the same size. The Cisco CWDM chassis enables rack mounting for up to two Cisco CWDM OADMs in a single rack unit.The Dual Single-Channel OADM device allows you to add and drop two channels of the same wavelength into two directions of an optical ring. The other wavelengths are passed through the OADM. Dual fiber is used for both network and GBIC (and SFP) connections. Eight options of this OADM are available, one for each wavelength: 1470, 1490, 1510, 1530, 1550, 1570, 1590, and 1610 nanometers (nm).