One of our customers wants to connect a remote PDQ machine to a Samsung OfficeServ 7200S. I have in the past used a Grandstream ATA, but only for an analogue phone and this worked OK. Has anybody used an ATA for a PDQ machine, if so which one?

Never done it, don't think it will work, as it's essentially a dial up modem Eric dint work well (if at all) over ip

Agreed. Try to avoid doing this - its' similar to installing a fax via an ATA - never a good option.