This is for the older style analog inbound only did trunks (DID - Direct Inward Dialing) , These type of trunks require that the customer supply battery (-48v), so obviously normal FXO cards won't work and can't be converted. after line connected will change to +12v. We know the FXS can supply battery and detect loop. The important thing is can it revers battery.
There are three electrical functions:
Loop current detection
Reverse Battery
Battery supply
From a signaling standpoint, the CO "loop" the line, then sends tones down to indicate which number was dialed (DNIS - Dialed Number Identification Service), the tones are not usually (although I think they can be) the dual tones like touch tone, but a single frequency tone.
As I know, cisco 2-Port FXS card can support those functions.
I think our FXS can reverse Battery, you can send out a polarity reverse signal to handle this. in the worst case, you can call a wctdm specific function call to enable it.