Yes, it is possible. To associate calls from the doorbell and the outdoor station with different tones, use terminal 9 of the 16-pin connector and the dedicated voice line for the doorbell (terminal 2) Alternatively, this input can be used in a "Bell" configuration using an N.O. (normally open) button connected to terminals 9 and 5 of the 16-pin connector, and setting the correct type of doorbell.