[Equipment] Ringdown with an ATA

I did not see anything on here with the search, so here goes: Does anybody know how to set up a ringdown line with an ATA? Ideally, just an HT-802 or equivalent 2 port FXS ATA stand-alone. I have seen several folks just use the Viking boxes, but I was sitting here thinking you should be able to do it FXS port to FXS port on an ATA. But I did not see any that had done so. Any suggestions? Hints? Thanks. KA0OUV [Tim]