Changing Terraneo Door Alarm Tone

[Guest biggi]

I just moved into an apartment building where there is a Terraneo door entry system.

There are two ringers, outside, and in the hallway. The outside ringer produces a very long, loud ringing tone, while the one in the hallway produces a much more pleasant single short tone.

Any clues as to whether I can rewire the unit to change the outside tone? Even something as simple as changing it to the same tone as the hallway tone?

Details:

Terraneo 601CEWS entry unit, white with a single black entry button on lower right.

Black cord to a white and black handset.