I would say some sort of service contract, with monthly/yearly payments to make. Does that help?

Hi 

We just started a concept together with a customer who sells monthly service subscribtion for licenses (Software). We are using the Service Contract for it since you can create invoices based on the invoicing intervals choosen by the customer. you can also add onetime sales or define the duration of the subscription.

bytsophan,

Are you only using the parts or also equipment on the service contract?

We have used both. Because the Sofware agreement is always connected to an Equiment