# Clock functions

The Switching service allows you to control the clocks
on the underlying MVIP
switching device. It provides functions for configuring the

- Board's clock source (H bus or network).

- Secondary clock signal on the bus.

- Netref clock source on the H.100/H.110 bus.

It also provides functions to retrieve clock configuration, timing reference, and status information.

The following table describes the clock configuration functions:

Function | Description
--- | ---
swiConfigBoardClock | Establishes the clock source for an MVIP board.
swiConfigNetrefClock | Defines the source of the NETREF clocks on the H.100/H.110 bus.
swiGetBoardClock | Retrieves information regarding the configuration of the board clocking and current status of the clocks.
swiGetTimingReference | Retrieves the status of a potential TDM bus clock timing reference.

All functions in the Switching service are synchronous
.

For more information, refer to Configuring the clocks.