For a long time, jacks and XLR connections were the preferred way of hooking up your speaker cabinet and your amp. Since the 200s, however, the Speakon connector (originally introduced by Neutrik) has come to dominate in models by nearly all manufacturers. And this is a development for the better, as Speakon connectors feature larger contact areas in comparison to XLR or jack connectors, and are touch-protected.
When you want to find out which connectors a cabinet you are considering features, you simply need to have a look at the reverse. You'll most likely find a rectangular connector panel with the sockets for the cables. Some manufacturers, by the way, are very customer-friendly and go for maximum versatility by featuring a number of sockets for different connectors - the combination of jack and Speakon sockets, at least, is still somewhat common. This can be a great advantage if you use an amp that is significantly older but don't want to miss out on a state-of-the-art bass cabinet: thankfully, with such speakers you don't have to bear the often considerable cost of an adapter cable!