S5700-52C-PWR-EI interoperability issue between CICSO IP phones

Problem Description :-

we used S5700-52C-PWR-EI to connect CICSO IP phone 7912 and 7960 . its not getting power.

Scenario:-

Analysis Process :-

we used huawei  and Avaya IP phone its getting power and working fine .

we checked interface POE power status and  found that  ,By default, the PSE does not check the capability of the PD

We enabled " poe legacy enable " -

When compatibility check is enabled, the device can detect and provide power for the PD that does not comply with the 802.3af or 802.3at standard. If compatibility check is not enabled, the device cannot detect and provide power for the non-standard PD