Need to buy a switch

[Syed Zia]

I need to buy a 24 or 48 port switch for my rack which also houses couple of
Asterisks boxes. I currently use an old 3COM Super Stack II 3300 with no
issues.

Any recommendations on what we should look when buying a switch for an
environment which has lot of voip traffic? Or it can be any good working
switch

Thanks

Syed