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Cisco ONS 15454 DWDM Reference Manual, R8.5
78-18343-02
Chapter 8      Transponder and Muxponder Cards
8.6.3    Automatic Laser Shutdown
Figure 8-15 TXP_MR_2.5G and TXPP_MR_2.5G Block Diagram
Caution You must use a 20-dB fiber attenuator (15 to 25 dB) when working with the TXP_MR_2.5G and 
TXPP_MR_2.5G cards in a loopback on the trunk port. Do not use direct fiber loopbacks with the 
TXP_MR_2.5G and TXPP_MR_2.5G cards. Using direct fiber loopbacks causes irreparable damage to 
the TXP_MR_2.5G and TXPP_MR_2.5G cards.
You can install TXP_MR_2.5G and TXPP_MR_2.5G cards in Slots 1 to 6 and 12 to 17. You can 
provision this card in a linear configuration. TXP_MR_10G and TXPP_MR_2.5G cards cannot be 
provisioned as a BLSR/MS-SPRing, a path protection/SNCP, or a regenerator. They can be used in the 
middle of BLSR/MS-SPRing or 1+1 spans only when the card is configured for transparent termination 
mode.
The TXP_MR_2.5G card features a 1550-nm laser for the trunk/line port and a 1310-nm laser for the 
client port. It contains two transmit and receive connector pairs (labeled) on the card faceplate. The card 
uses dual LC connectors for optical cable termination. 
The TXPP_MR_2.5G card features a 1550-nm laser for the trunk/line port and a 1310-nm or 850-nm 
laser (depending on the SFP) for the client port and contains three transmit and receive connector pairs 
(labeled) on the card faceplate. The card uses dual LC connectors for optical cable termination.
8.6.3 Automatic Laser Shutdown
The ALS procedure is supported on both client and trunk interfaces. On the client interface, ALS is 
compliant with ITU-T G.664 (6/99). On the data application and trunk interface, the switch on and off 
pulse duration is greater than 60 seconds. The on and off pulse duration is user-configurable. For details 
regarding ALS provisioning for the TXP_MR_2.5G and TXPP_MR_2.5G cards, refer to the 
Cisco ONS 15454 DWDM Procedure Guide.
SFP Client
Switch
Switch Driver
Tunable
Laser
Switch Cross
Switch
Limiting
Amp
Limiting
Amp
Main
APD+TA
Protect
APD+TA
Mux
Demux
Mux
Demux
Mux
Demux
CPU
Main
ASIC
Protect
ASIC
FPGA
SCL
FPGA
SCL BUS
2R Tx path
Trunk
Out
2R Rx path
CELL BUS
CPU
I/F
CELL
BUS
DCC
CPU to
GCC
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