16/44.
To elaborate, if you have your 722 set-up to accept a SPDIF signal, and use the external Word Clock (that of the DAT PLayer), it should aumotacially lock into whatever it needs (16/44 or 16/48)... Someone with more experience with the 722 can tell you more... But it shouldn't let you record a 44k at 48k, unless you have it running through the analog input...
For me, I have to set my HD-P2 to whatever signal it is, and then it will record. Otherwise, it won't start... And if and when the DAT changes from 44 to 48, it will stop recording, though if it goes from 48 to 44, it will continue (HD-P2 defaults to 48k)...
I had a Nomad Jukebox3 that would let you record a 44k at 48k (and vice versa), but the error was obvious upon playback (too slow or too fast)...
Terry