I have a question regarding the naim unitiserve I have a dac (non naim) with optical in and I noticed that the unitiserve has optical out could I use the unitiserve with a non naim dac?
Yes, that should be possible ...
Yes, the digital output formats are fairly standard. The UnitiServe manual will tell you the formats it can output -- your dac may be happier with more (or fewer formats) but overall you're limited to what the UnitiServe supports.
You have a choice of optical or coaxial SPDIF output, and you should be able to use it with pretty much any DAC that has either of these inputs. The preferred connection by many Naim users is the coaxial one, but either would be fine.