Intercom or doorbell — serviced once a year (per device)
Added to an annual package (ready, custom or institution); not sold on its own.
Servicing the intercom or doorbell, once a year.
Unit: per device. Carried out during your scheduled annual subscription visits, with a photo report after each visit.
The engineer confirms the numbers at the first visit: any excess is charged and any shortfall refunded. The price is fixed for the subscription year.