CHAPTER
 
3-1
Cisco ONS 15454 DWDM Reference Manual, R8.5
78-18343-02
3
Optical Service Channel Cards
This chapter describes the optical service channel (OSC) cards for Cisco ONS 15454 dense wavelength 
division multiplexing (DWDM) networks. For installation and card turn-up procedures, refer to the 
Cisco ONS 15454 DWDM Procedure Guide. For card safety and compliance information, refer to the 
Cisco Optical Transport Products Safety and Compliance Information document.
Note Unless otherwise specified, “ONS 15454” refers to both ANSI and ETSI shelf assemblies.
Chapter topics include:
 • 3.1  Card Overview, page 3-1
 • 3.2  Class 1 Laser Safety Labels, page 3-2
 • 3.3  OSCM Card, page 3-4
 • 3.4  OSC-CSM Card, page 3-8
3.1 Card Overview
This section provides card summary and compatibility information. 
Note Each card is marked with a symbol that corresponds to a slot (or slots) on the ONS 15454 shelf assembly. 
The cards are then installed into slots displaying the same symbols. See the “1.16.1  Card Slot 
Requirements” section on page 1-61 for a list of slots and symbols. 
An optical service channel (OSC) is a bidirectional channel connecting two adjacent nodes in a DWDM 
ring. For every DWDM node (except terminal nodes), two different OSC terminations are present, one 
for the west side and another for the east side. The channel transports OSC overhead that is used to 
manage ONS 15454 DWDM networks. An OSC signal uses the 1510-nm wavelength and does not affect 
client traffic. The primary purpose of this channel is to carry clock synchronization and orderwire 
channel communications for the DWDM network. It also provides transparent links between each node 
in the network. The OSC is an OC-3/STM-1 formatted signal. 
There are two versions of the OSC modules: the OSCM, and the OSC-CSM, which contains the OSC 
wavelength combiner and separator component in addition to the OSC module.
The Mesh/Multiring Upgrade (MMU) card is used to optically bypass a given wavelength from one 
section of the network or ring to another one without requiring 3R regeneration.