Fax Transmission Protocol - T.30

The T.30 Recommendation defines the procedures which are necessary for document transmission between two facsimile terminals in the public switched telephone network.

These procedures essentially comprise the following five separate and consecutive phases as shown in Figure [*]:

  
Figure: Time sequence of a facsimile call

• Phase A - Call establishment
• Phase B - Pre-message procedure
• Phase C1 - In-message procedure
• Phase C2 - Message transmission
• Phase D - Post-message procedure
• Phase E - Call release
• Signalling