during record, signal will not exceed -4dBFS

There is a trim adjustment for each input and each output, those which are on the 888/24's front panel. You mention that digital signals into the unit do not have the same problem, which definitely points to analog A to D converters not receiving signals hot enough to make 0dbfs. The 888's input trims and/or +4/-10 jumpers are not set to match the analog signals feeding into your 888 inputs. The +4/-10 adjustment you mention is done with jumpers inside the 888's case. Which are you set for? The jumpers get you into the right ballpark, (are you interfacing to "pro" gear with +4 signal levels, or are you interfacing to "semipro" gear with -10 signal levels) and the trims allow you to make considerable variations to fine-tune both input sensitivity and output level of the 888. I think you should get your hands on a meter that can read RMS AC voltages in order to verify the trouble. For most "pro" setups, reference level (-20dbfs in the USA) sinetome coming from the signal generator plugin directly to a single output should read 1.23VRMS (AC). Rather than repeat setup procedure here, you should be able to find a good guide in the Pro Tools manuals. I can't recall if it is the thick manual or an 888 setup manual. Good luck.

Problem solved...the I/O's were set to -10 on input, +4 for their outputs. I honestly do know how to calibrate a recording device. (I came of age in the days of 2" 24 tracks. Oy!) But I was fooled by thinking that the inputs and outputs could not be independently switched. As you're probably aware, not only can they be independently switched, individual channels can be either -10 or +4. Thanks for your help Richard. Peter

Judging by the hour of your post, you've had a good end to a very long day! You're welcomed.