PHax

PHax is a Windows fax application that sends and receives faxes through an ordinary USB fax modem — no fax server, no online fax service, and no dependency on the Windows Fax Service or "Windows Fax and Scan".

It drives Fax Class 1 / Class 1.0 (EIA-578 / ITU-T T.31) modems directly and implements the fax protocol itself: T.30 session negotiation, V.21 HDLC framing, training and speed fallback, and T.4 page coding, written in C#.

Desktop app (WinUI 3): Incoming, Inbox, Drafts, Outbox and Sent; compose with PDF/TIFF/image/Word attachments and cover pages; scan paper documents from WIA or TWAIN scanners; preview, print, forward, PDF export; progress popup and Windows notifications. Windows Service: owns the modem, answers calls, sends the queue with automatic redial, keeps working when nobody is signed in, and prints received faxes automatically if you want it to. Safe delivery accounting: a fax is only marked Sent after the receiving machine confirms every page. If pages went out without confirmation it is marked Unconfirmed and never resent automatically.