I find it typically said that the maximum Cat6a cable distance is 100m for 10GBASE-T.
But often for a 10GBASE-T SFP+ transceiver, the product is said to support a maximum of 30m. For example: Cisco SFP-10G-T-X
What does the 30m really mean? Does it mean that using the transceiver actually reduces the maximum cable length by so much, perhaps by introducing signal loss somehow? Or perhaps the transceiver sends a lower-power signal than a built-in RJ45 port and so cannot cover as long a distance?
For using cables longer than 30m for 10GBASE-T, is it better to use built-in RJ45 ports instead of SFP+ tranceivers?
EDIT: Removed the incorrect part about Cat8.