Provide me the details of different indicators of tellabs [model : Stu-160]

We are using using (bandwidth 128) lease line for transferring live data, But alternative days we are lossing the connectivity.
When It is working STU Shows All LED Light IS UP(103,104,105,106,108,109) both location.
When Connection is lossing STU Shows 103 LED Light IS down one side
Another side 104 Led is down.
Alternative days we are getting the connection,
Could you please help me to solve this issue,
Thanks and regards,
Mohammed Aslam.A