Alcatel-Lucent MDR-8000 User Manual page 69

Both RCVRs at the other end have a problem and have switched the
XMTRs to try and clear it. If the RCVRs clear within a defined time frame
(which we will hereafter call the CLA window) after switching, the CLA
appears. if the RCVRs clear by switching or any other way outside of the
CLA window, the CLA does not activate, but switching continues.
Switching times vary, depending on RSL.
If RSL is above alarm threshold, the first XMT switch occurs 5 seconds
after the problem at the RCVRs is detected. The 5 seconds following the
first XMT switch is the "CLA window". If the RCVR alarms clear during the
5-second CLA window, the CLA will activate at the XMT end.
Since the RSL at the RCVRs is ok, equipment failure at the farend XMTR is
the most probable cause of the RCVRs failing.
If RSL is below alarm threshold, the first XMTR switch occurs 30 seconds
after the problem at the RCVRs is detected. The CLA window is the first 5
seconds of the second 30 seconds. If the RCVR alarms clear during the
5-second CLA window, the CLA will activate at the XMT end.
In DS1 and OC3/STM-1 2-fiber switched and 4-fiber switched radios, if the RCVR alarms do not clear within the CLA window, after
ten 30-second periods (10 switches) the controller switches the I/O Interface modules and another 5-second CLA window is
opened. If the RCVR alarms clear during the 5-second CLA window following the I/O switch, the CLA will activate at the XMT end.
Since this is a silent alarm at the XMT end, no other alarm should show up at the XMTR.
Clearing the RCVR problem does not automatically clear the CLA at the XMT end. The CLA can be cleared using the ACO
switch on the controller module or by rolling the mouse over RF Common Loss on the screen and double clicking.
CLA can be caused by many things. Troubleshooting is RSL dependent. Problems that can cause a CLA follow.
1. Path problems, such as fading, refraction, interference
2. Frequency problems due to aging or bad crystal oscillator
3. Bad capacity key on XMTR
4. Bad RF cable
5. Bad RF switch
6. Bad I/O Interface
If RSL is normal, look for a digital signal problem at the XMT end. The RCV end will probably have Eye Closure and Frame
Loss alarms, but not an RSL alarm . Since the RCVRs are receiving a strong signal (but not a good signal) from the farend
XMTR, the RCVRs will probably be locked on frequency.
Is RSL above or below alarm threshold?
Above, go to 1.
Below, go to 2.
1. If RSL is ok, look for a digital signal problem at the farend XMTR:
a. Check XMTR capacity key.
b. Remove/replace XMTR.
c. Remove/replace I/O Interface.
2. If RSL is low, there will be a RCVR RSL alarm along with any others:
a. Check for prolonged fade. Use USI RSL screen and check history. Worst fading times are early in the morning and
late in the evening.
b. Look for equipment failure at XMT end:
Check for bad XMTR/PA. Verify correct output power out of XMTR/PA. Is output power correct?
Yes, check for bad cable or RF switch at the XMT end.
No, remove and replace XMTR, PA, I/O Interface, in that order.
Figure 5 - 3 Troubleshooting Radio XMT Alarms (Sheet 2 of 2)
TRANSMITTER
STATUS
A
Transmitter Fault
Transmitter OnLine
RF Common Loss
PA Temperature
PA RF Power
Transmitter RF Power
ATPC High Power
ATPC Timeout
Sync Loss
MDR-1092
12/06/07
5-11