Configuring Internal Clock as Clock Source
                                            You can configure the device to use its internal clock source. The internal clock source is a stratum 4E-compliant clock source. When the device has no line interfaces, the device should be configured in this mode.
                                            
                                                
                                                
                                                
                                                
                                                    |  | ➢ | To configure internal clock as clock source: | 
                                            
                                            
                                                
                                                
                                                
                                                
                                                    |  | 1. | Configure the clock source as the device's internal oscillator: | 
                                            
                                            
                                                
                                                
                                                
                                                
                                                    |  | a. | Open the  TDM Bus Settings page (Setup menu > Signaling & Media tab > Gateway folder > TDM Bus Settings). | 
                                            
                                            
                                                
                                                
                                                
                                                
                                                    |  | b. | From the 'TDM Bus Clock Source' drop-down list [TDMBusClockSource], select Internal: | 
                                            
                                            
                                                 
                                            
                                            
                                                
                                                
                                                
                                                
                                                    |  | 2. | (E1/T1 Trunks Only) Configure the line to drive the clock on all trunks: | 
                                            
                                            
                                            
                                                
                                                
                                                
                                                
                                                    |  | b. | From the 'Clock Master' drop-down list [ClockMaster], select Generated (for all trunks): | 
                                            
                                            
                                                
                                            
                                                
                                                
                                                
                                                
                                                    |  | 3. | Restart the device with a save-to-flash for your settings to take effect. |