The Output Power of the DTX CableAnalyzer is very small. There is little danger of the DTX CableAnalyzer damaging an active port on a hub/switch.
Output power of DTX depends on frequency. Here are typical values:
A quick answer (for 1 to 600 MHz) would be "about 0 dBm", or "about 1 milliwatt", or "about .32 VRMS across the pair under test", or "about .9V peak to peak across the pair under test".