Exchange 2013 standard vs enterprise

That is the case, yes. An Enterprise CAL won't give users on a Standard server more rights. You need the Enterprise server for that to function.

CorinTack is wrong.... just FYI.

Its confusing but what it actually has is two parts.

You have exchange server standard and exchange server enterprise, the only difference here is the number of mailbox databases that you can use. So you will be fine with Standard for that part.

You then have to purchase licensing to allow your users to connect to the exchange server, these are called CAL's or Client-Access-Licenses. If you have 300 users you need to buy 300 CALs. If only some of your users will have Unified Messaging then there is no point buying all 300 the same level (enterprise CALs).

This allows you to buy the 300 "required" (standard CALs at a cheaper rate) and then 200 users with Unified Messaging on top of it (enterprise CALs at a higher rate).

Also you can typically migrate CALs from your old exchange to your new one.

Does that make sense?

So Exchange Standard License (for your server).
Then a mix of Standard and Enterprise CALs depending how many users you have.

So i'm still a bit confused. So whatever features the exchange 2007 came with is good, but we want Unified Messaging with exchange 2013.  So do I need to be exchange 2013 enterprise to be able to use unified messages, or will the standard version provide unified messages.  In the above messages, and according to the website requirements, looks like I need the exchange enterprise user CALs to make usre Unified Messaging works.

Am I wrong?

So.
You only need Standard Exchange for the server, as you already have.

For the Client Licenses though (every user that is going to connect) you need 1 Standard CAL per user. So if you have 300 users then that is 300 Standard CALs.

Then for every user you want to have Unified messaging you need to buy an Enterprise CAL. If all your users need unified messaging then you need 300 Enterprise Cals.

EDIT: Apologies, i misread you original post you have 90 users with 300 mailboxes... you only need to license your Users so 90 of each, not your 300 :)

I only have about 75 users, let's say 80.   I have over 200 email accounts, but they are not really tied to a user.  

So basically, I just need to buy 80 enterprise cals and that's it.  I don't need to buy 80 standard cals and enterprise cals, as that makes no sense.

Got it.  Thanks.

is there a website that displays the differences between the standard and enterprise editions?

Is the ONLY difference the mailbox databases restriction?  So far, all my users now are under 1 mailbox database, so that doesn't even matter to me.

So basically, if I'm understanding you correct, the standard edition and the enterprise edition has exactly the same features or options, the ONLY difference is with the enterprise edition, you can have up to 50 or 100 mailbox databases?

Unfortunately thats what it says.
If you already have the Standard CALs you can transfer them from your old server.
You then need to buy 80 enterprise CALs (they are add-ons).

From the link you posted:

"The Enterprise CAL is sold as an add-on to the Standard CAL—to enable Enterprise CAL features, the user must be licensed with one Standard CAL plus one Enterprise CAL."

So do I need to buy standard and enterprise, or can I just buy the enterprise CALS?

That website is good, but I need one for exchange 2007 to 2013

Thanks everyone for your help.