NSN 2G

[rf _engg]

Hi all,

we are working on NSN 2G ,we are receiving a alarm in my network

Alarm no.:- 7601

Alarm description - Difference b/w PCM ans BTS freq reference

Please help to resolve it

[plaosan]

you can use frequency counter to adjust 13 Megaherzt in BOIA

[mohyedeen_alkousy]

7601 BCF OPERATION DEGRADED
usually this alarm has many reasons but according to the detail that you give " Difference between PCM and base station frequency reference"
this means that the reason is PCM synchronization problem , below is the actions proposed according to document :

1. Check the network synchronization between the BSC and the base station.
2. Check the transmission synchronisation settings on the transmission card.
3. Check the transmission cabling at the site.
4. Replace the BOI.

Note: After corrective actions, it may take several hours to adjust the clock and the alarm to disappear.
Note: With BTS SW CX5 and the implementation of the Fast Tune feature, you may set the DAC clock control word via BTS Manager. This will initiate a Fast Tune procedure, in which the 26 MHz oven oscillator is quickly (within minutes) set very close to the correct frequency.

[adewijaya]

7601 BCF OPERATION DEGRADED
usually this alarm has many reasons but according to the detail that you give " Difference between PCM and base station frequency reference"
this means that the reason is PCM synchronization problem , below is the actions proposed according to document :

1. Check the network synchronization between the BSC and the base station.
2. Check the transmission synchronisation settings on the transmission card.
3. Check the transmission cabling at the site.
4. Replace the BOI.

Note: After corrective actions, it may take several hours to adjust the clock and the alarm to disappear.
Note: With BTS SW CX5 and the implementation of the Fast Tune feature, you may set the DAC clock control word via BTS Manager. This will initiate a Fast Tune procedure, in which the 26 MHz oven oscillator is quickly (within minutes) set very close to the correct frequency.

in my experiences moslty contributed by cabling at the site and bad BOI, so number 3 and 4 that frequently happend on live network

[K4CrUt]

7601 BCF OPERATION DEGRADED
usually this alarm has many reasons but according to the detail that you give " Difference between PCM and base station frequency reference"
this means that the reason is PCM synchronization problem , below is the actions proposed according to document :

1. Check the network synchronization between the BSC and the base station.
2. Check the transmission synchronisation settings on the transmission card.
3. Check the transmission cabling at the site.
4. Replace the BOI.

Note: After corrective actions, it may take several hours to adjust the clock and the alarm to disappear.
Note: With BTS SW CX5 and the implementation of the Fast Tune feature, you may set the DAC clock control word via BTS Manager. This will initiate a Fast Tune procedure, in which the 26 MHz oven oscillator is quickly (within minutes) set very close to the correct frequency.

We ever have got similar problem in our network, most of the bts have that alarm but not all, instead of 4 actions above that mostly 3&4 frequently happen in the network (like adewijaya said), our problem solved by reset the site(BCF) that have the alarm (note : the alarm not happen in all sites but in several sites and the transmission link is different)

BR,

[rf _engg]

thanks for Suggestion ... i will check