clinton wrote:what does it sequence?
When you play parts in your synth it's actually transmitted as MIDI data to the sound module part of the synth. The sequencer can collect that data and store it the same way it's done in a computer. So it sequences a performance essentially, which then can be played back using whichever patches you want from the sound module (or like Christian said to the sound modules in other equipment.)
Andrew's concern (which is valid) is that many sequencers built-in to synths are not very intuitive and are not as flexible as the ones found in computer based sequencers