Does GreenLink Support Fax Machines?

Yes, GreenLink Hybrid Fax Solution does. For $29.99 a month, you get 1 ATA device (that you can plug into the network and connect to a physical fax machine). In addition to this, all the users can also fax from the Customer Portal. The service includes 200 outbound pages, and it is 8 cents per page thereafter.  

Incoming faxes are always free and unlimited and come with the account.

The other benefit you have on the incoming side is that in addition to those faxes being on the portal, the customer can also have them delivered by email and decide if the faxes will be printed on the fax machine or not.