[Serusers] ser, pstn gateways

Hello all, Im using ser, with esteras softphone, and a couple of cisco ata186's. I have to say I really like ser, as it is small fast, and reliable without being over complicated. I would like to know what other ser users and developers use for pstn gateways? I have a openline4 card from voictronix, but there is no software support for sip (When I bought it I thought I would use h.323). I have looked at cisco's pstn gateway modules, but was turned off them because of price, and lack of clear straight forward information to name but two reasons. Ideally what I would like to have is a solution that would support at least 4 pstn lines (expandable to maybe 8), that would run on FreeBSD (or at worst linux), works well with sip & ser, with high quality audio, and minimal delays when dialing in out. TIA, -Emil