mojno, est' neskol'ko variantov:
1) Postavit' platu KX-TDA0484XJ, dorogo ((
2) Kupit' FXO/FXS adapter (Syslink SPA400 ...)
...
+ postavit' Soft BPX (FreePBX, Asterisk, OpenSER, ...)
3) Podkluchit'sya k Cisco AS55xx, Cisco 2811 ... pri/bri