This object selects which local clock source used to drive the transmit data for the port. This option is not available when the port's timing mode is loop.

oscillator(1) selects the on board oscillator.

busLine8K(2) selects the 8 KHz clocking bus line. All CSM-interface types except for OC3 and OC12 can use an 8 KHz clock from the bus to generate their local timing.

busLine19M(3) selects the 19.44 MHz clocking bus line. All CSM OC3, OC12 and CSM-AB-CE-T1 and CSM-AB-CE-E1 interface types can use a 19.44 Mhz clock from the bus to generate their local timing. In the case of the CSM-AB-CE the adapter board does a divide operation on the 19.44 Mhz clock to get an 8 Khz clock to use.

Currently, only the CSM-AB-CE T1 and E1 adapter boards have the ability to support either busLine8K and busLine19M options.