alters vs personality states

What is the difference between alters and personality states? In some of my reading it mentions personality states can be present instead of full fledged alters as a requirement to be classified as DID. Is it possible to remember everything when these are out, but not be able to communicate or control them? I do have instances where I think I am me, but then someone mentions something that happened an hour ago and I don't know what they are talking about. At the same time I have times where I think I am me, but nothing I am doing/saying is within my control. I've been trying to communicate at least weekly (or more) for over a year, but really not getting anything I can say definitively comes from an alter.

Hope this makes sense!

I am not sure of the clinical answer. I can answer based on my experience though.

My counselor knows I have multiple "sides." Or "states." She however wanted to confirm I did not have the psychotic feature of feeling like the states were completely different from each other with their own voices and their own memories. I don't hear my others' voices, it is all my own voice, and they are all a part of me.

For instance, on the bus ride, I often get paranoid and dissociate. I feel as if three voices are arguing in my head. one is a little girl character who is always anxious, one is a sarcastic but helpful guardian character, the other is this angry kid characters whose desires are very male. They are all me, like I don't hear distinct voices in my head. I just have these very conflicting desires from within myself. Categorizing helps me, and listening to what each parts have to say is helpful, but rarely if ever do I feel like I am all one or the other character, rarely if ever does one take over, rarely if ever do I forget what I did as one character and not remember it when I switch to another character.

In other words, if you hear seperate voices in your head, or if your alters completely take you over, or if certain alters remember events that others do not, those are true Alters, and you have DID. If the alters are not quite so distinct, and you know full well they are all part of you with your own same voice, and you have relative control of them, this just means you have different "states" of mind and you may have Dissociative Not Otherwise Specified.