Hi inbox  ;^)

The short answer is that it can handle as many concurrent connections as you
have CALs.  SBS2k had an upper limit of 50 connected devices (with each
device consuming a CAL once it was first connected.  Therefore, if you had
15 devices connecting to your SBS, but only had a maximum of 8 concurrent
connections, you'd still have to have 15 CALs - one for each unique device.)

With SBS2k3, the upper limit has been raised to 75, and licensing has been
split between device & user CALs.  In SBS2k3, a device CAL works just like
the CALs in SBS2k - you need one for each unique device connecting to your
SBS.  User CALs however, apply to each user.  There's been some debate as to
whether this applies to "user account" or "individual user" - my take on
reading the EULA is that this applies to each "individual user".  Therefore,
if you had 10 users, and several users connected from multiple devices (e.g.
work pc, home pc, pda, smart-phone, etc.) - each User CAL allows an
individual user to access the server from multiple devices *simultaneously*
while only consuming a single CAL.  Therefore, it is perfectly conceivable
that you could have 20 concurrent connections with only 10 User CALs and be
perfectly legal (assuming 10 Users accessing the server from 2 devices each
simultaneously).

HTH!