SSCA Part 4 SIP and FoIP

T.30 Fax Signaling:

Sending Fax-------------|---PSTN---| Receiving fax
-------------------------------------------->>calling tone CNG
--------------------------------------------<<Called tone CED
--------------------------------------------<<Dig Identification Signal DIS
-------------------------------------------->>Dig Command SIgnal DCS
--------------------------------------------Training Check TCF
--------------------------------------------<<Confirmation
-------------------------------------------->>Fax page transmission
-------------------------------------------->>End of procedure EOP
--------------------------------------------<<Message Confirmation MCF
-------------------------------------------->>Disconnect


**Fax over IP**
pstn fax machine T.30>>Fax gateway>>G.711 pass through>>pstn gateway>>convert to T.30>>fax machine


Protocols:
G.711 Pass through
T.37 Store and Forward
T.38 relay


T.37: Standard protocol for encapsulating the fax document and send via email

uses Store and Forward method but it is NOT widely used.

T.38: Defacto standard for real time FAX. it resolved G.711 packet loss isssues

T.38 and G.711 network traffic

SIP.fax Tagging: 
If one Fax No having multiple devices such mobile/fixed phones >>the one with sip.fax will receive