Emerson PMC-CGM manual Configure the Reference Clock

Configure the Reference Clock Access and Configuration

4.4.7Configure the Reference Clock

You can define the reference clock source, the frequency and the priority of the reference clock inputs. For a description of the respective MIB objects refer to Table "cgmInputTable" on page 47.

Reference clock sources are:

zBITS interface 1 (input 3, frequency automatically configured via interface mode)

zBITS interface 2 (input 4, frequency automatically configured via interface mode)

zLinecard reference clcok A (input 7)

zLinecard reference clock B (input 12)

For the slave, the reference clock is always the Master/Slave synchronization clock. This is automatically configured.

When you initially assign priorities, we recommend to start with the highest priority input. Otherwise, the PLL may switch inputs unnecessarily or end up locked on a low-priority input while a higher priority input is also valid.

If you want to change the selected PLL input by changing the priority, you have to change to revertive mode first (cgmProtectionRevertiveModeState OID:.1.3.6.1.4.1.3656.8152.1.1.18.0).

Configuring the reference clock source for the T0/T4 path

To configure the reference clock, proceed as follows:

1.Start SNMP manager or MIB browser.

2.Connect to the PMC-CGM using one of its IP addresses.

3.Go to cgmInputFrequency object OID:.1.3.6.1.4.1.3656.8152.1.1.1.1.3.<instance number which is equal to input number -1>.

4.Select the desired input frequency. The following values are possible:

0:8 KHz

1:1544 KHz / 2048 KHz, depending on E1/T1 operation.

3: 19.44 MHz

5.Go to cgmT0InputPrioritiy object OID:.1.3.6.1.4.1.3656.8152.1.1.1.1.4.<instance number which is equal to input number -1>.

6.Select the desired input priority.

A priority value from 2 to 15 is used by the T0 PLL to select an input. A lower numerical value means a higher priority. A value of 0 disables the input, that means it will not be selected as reference clock. A value of 1 cannot be set as it is used for the master/slave synchronization clock.

Default value is 0.

This setting is applied to the protection partner as well.

PMC-CGM Installation and Use (6806800D53C) 41