To keep the SBC T1/E1 interface in sync with the PSTN, ensure the following:
When there is no PSTN connection, SBC 1K/2K Clock Source must be configured for System and the device connected to SBC1k/2K should derive clock from SBC1K/2K.
The System Clock Source setting applies to the TDM interface, and has no relationship to the system time.
To configure system timing using a network clock source:
In the left navigation pane, go to System > System Timing.
Specifies the source of the systems transmit clock.
Specifies the DS1 port from which the clock will be derived. This field is visible only if Network is specified as the Clock Source.
Specifies the DS1 port from which the clock will be derived. This field is visible only if Network is specified as the Clock Source.
The Secondary Clock Source is used only if the primary clock source is not of sufficient quality or becomes unavailable.
Indicates the status of the current active clock.
If the primary clock source goes down for whatever reason, the system will attempt to switch to the secondary clock source. If a secondary clock source is not configured here, the Status field will display as Free Run (uses the internal clock).
Possible values:
Primary. Indicates the Primary Clock Port is used.
Secondary. Indicates the Secondary Clock Port is used (if the Primary Clock Port is down).
Free Run. When the Primary Clock Port is down and a Secondary Clock Port is not configured, this indicates the clock source is the internal system clock.