Turn a legacy PBX (Panasonic) into a FXS/FXO card

Hi Folks,
I’m just thinking that not-expensive Panasonic (say 6x16) PBX costs $300 but provides 16FXS+6FXO - and in fact it’s just a kind of a computer hardwarely using a boards with that number of the interfaces. I’m wondering if anyone tryed to disassemble a PANASONIC PBX and make a hardware data interface to it’s internals to utilize this great amount of ports DIRECTLY.

Please note: I do not mean connecting FXO interfaces on the Digium FXO cards to an FXS ports on the Panasonic PBX -
I do want to turn a Panasonic PBX to an FXS/FXO Interface card

Any ideas?