2 ch analog in (on XLR/TRS combo, one of which can take an instrument in), 2 ch analog out (on TRS and RCA), digital in/out (on optical), MIDI I/O. The specs state: "DIGITAL IN 'OFF': Full duplex (except for 96 kHz setting). DIGITAL IN 'ON': Recording only". Full duplex means being able to listen back while recording. This statement means that when the sample rate is not set as high as 96k, and the digital input is off, you can listen back while recording. However, if the sample rate is set to 96k, or the digital input is on, you can not listen back while recording.
Notice the "advanced driver" switch on the back. If this is set to "off," the UA-25EX is only a 16 bit/44.1k device.
"USB 2.0 Compatible (works as a USB 1.1 device without changing the specifications and performance)."
"The newer "Cakewalk by Roland" UA-25EX replaces the same product previously branded "EDIROL by Roland" from second half of 2009." This is apparently just a rebranding, with no feature changes.