The AP-124 and AP-125 have some built-in intelligence to manage power consumption based on what's available from POE. If there's not enough power available to run the AP in full-function mode (power profile 1), the second ethernet port will be disabled (power profile 2). When powering the unit from a marginal 802.3af POE source, using long Ethernet cables, and/or lower quality cables, further reduction of power consumption may be needed, and the AP will change from 3x3 to 2x3 mode (power profile 3; the third transmit chain is switched off). The impact of this on performance is marginal.
Power profile 3 can be supported from any 802.3af POE source, using any cable type and length.
Power profile 2 can be supported in most typical cases using 802.3af
Power profile 1 may be supported from 802.3af, but is guaranteed from POE+ or 802.3at.