Center Tap (CT) pins in RJ-45 Connector
The value for the CT capacitor will not be in the datasheet of the PulseJack connector.
How to connect the CT pin will depend on the Ethernet PHY interface that will be connected to the device side. So suitable circuit examples should be in the Ethernet PHY datasheet.
Sometimes the CT pin will be connected to some kind of supply voltage to bias the PHY data pins. Sometimes the PHY data pins are already biased, so then it might just need a capacitor for common-mode signal filtering.
Also you should not blindly believe everything found on the Internet.

On the LAN side they usually have an isolated DC supply added to them
to alert the other end of the link that it is 'live'

The above quote is simply not true. No, usually there is no isolated DC power supply on LAN side, and even if there is, it is for Power Over Ethernet, and it is not used to alert the other end of the link that it is live.