Annual Maintenance Contracts generally includes replacement of defective parts/ replacement of whole units along with On-site support. Sometimes, Annual Maintenance Contracts would require the customer to hand over defective units/ send them over by courier (to the manufacturers facility) which would be returned to them after the fault is rectified.

If On-site support is not provided by a vendor, customer would log-in a complaint (through web or phone) and the service desk personnel would contact the customer to identify the exact fault. They can even access the network based equipment from a remote location (if remote access is enabled by the customer) to identify the fault, and try to rectify it. If the problem is identified as a hardware defect, the vendor normally ships a new unit in advance and the customer is required to send the old dysfunctional unit back to the vendor.