Mono and Portamento are effects that can add a great "Retro" feel to a sound. Mono sounds will only play one note at a time. Portamento is an effect that causes a pitch slide between notes. This works great on synth leads and some bass sounds. Try sending these values from your sequencer:

Controller Value
CC 126 01 Mono on.
CC 65 127 Portamento on, a value of 0 turns it off.
CC 5 40 Portamento Time. Higher values create longer
slide times.