Revised September 28, 2005
September 11, 2002
NOTICE:
THIS FIELD NOTICE IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF THE INFORMATION ON THE FIELD NOTICE OR MATERIALS LINKED FROM THE FIELD NOTICE IS AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS FIELD NOTICE AT ANY TIME.
Products Affected
|
Product |
Comments |
|---|---|
|
15808-TT-25G-Cxx |
Line Transponder - 2.5 Gbps - C band - Channel 01-80 |
|
15808-LT-25G-Cxx |
Line Transponder - 2.5 Gbps - C band - Channel 01-80 |
Problem Description
After sending LASEROFF OFF and LASEROFF ON commands, in sequence, either through local craft or through TL1 interface on Transmit Transponder units listed above, the next receiver in the route starts detecting B1 and B2 errors.
Background
During LASEROFF OFF status the Modulator is not switched Off and so the relative Vbias working point can drift. This misbehaviour causes that after LASEROFF ON command the Modulator works on a wrong working point and thus the errors.
Problem Symptoms
A Receiver in a route detects B1 and B2 errors after switching Off and then On the previous TT/LT laser.
Workaround/Solution
The suggested solution is to switch the laser On and then perform a hardware reset on the unit. Extracting and re-inserting the unit will accomplish this.
It is strongly suggested to avoid using the LASEROFF OFF command. To get the unit to show the same behavior (in case some tests require it) it is possible to disconnect the input signal fiber.
DDTS
To follow the bug ID link below and see detailed bug information, you must be a registered user and you must be logged in.
|
DDTS |
Description |
|---|---|
|
CSCuk36903 (registered customers only) |
TT25G: laser off condition cause modulator drift |
|
CSCuk36921 (registered customers only) |
LT25G: laser off condition cause modulator drift |
For More Information
If you require further assistance, or if you have any further questions regarding this field notice, please contact the Cisco Systems Technical Assistance Center (TAC) by one of the following methods:
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