According to the camera user guides linked below, the C40 is only compatible with the PrecisionHD Cameras 1080p12x and 1080p4x, while the SX80 is the only codec compatiable with the Precision 60.
PrecisionHD Camera Guide, pg 13.
Precision 60 and SpeakerTrack 60 Camera Guide, pg 9.
However, I just tested and you're able to use both a PHD12x and P60 camera together even though it isn't a documented solution. The Precision 60 camera will connect directly to the codec via RJ45, in the case of the C40, connect it to the second RJ45 port below the LAN port.
The RJ11 to RJ45 cable is for daisy chaining PrecisionHD cameras together and doesn't apply to the Precision 60 camera, refer to the PrecisionHD guide starting on pg 21 for information on daisy chaining.