CTP151 Modules Slot and Port Numbering
The CTP151 device has removable interface modules from the front, but no removable fan trays.
In the CTP151 device, slot numbering is from left to right, 0 to 1. Any single module must be installed in slot 0, and any single clock connection must come from the port in slot 0.
CTP151 port numbering on the front panel for the serial interface module is bottom left 0, top left 1, bottom right 2, and top right 3.
Port numbering for the T1/E1 interface module is 0, 1, 2, and 3, from right to left with a clock port at the far right.