Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?


CTP150 Clock Module


Clock interface modules provide clock distribution between modules when the backplane is in use by voice applications. For the CTP150 model, the serial and T1/E1 interfaces each have a clock port, although only one port needs to be used for both interfaces. One port is of the HD-26 connector type, and the other is of the RJ-45 connector type.

On the CLK port, differential clock signals are output on the pins 4 and 17 of the HD-26 connector. When an EIA-530A DCE-F serial cable (CTP150-CBL-DB25-DCE-F) is connected to the CLK port, the TT pins 24 and 11 of the DB25 connector output clock signals. If you configure a 32 kHz reference output, an RS-422 32 kHz clock signal is generated on the pins. Even if you disable the 32 kHz reference output and configure an external clock reference, the module expects an RS-422 clock input (of the configured frequency) on the same pins.


The external clock reference port must be connected to any module that is in slot 0, the left-most module slot on the chassis.