AddPac VoiceFinder AP200 User Manual page 181

VoiceFinder AP200 VoIP Residential Gateway (RGW) User's Guide Version 1.1
relay, all gateways and gatekeepers in this network are able to send faxes to
other remote offices or to the offices of another company on the IP network.
For example, when a fax is sent from the originating gateway, a voice call is
established. The terminating gateway detects the fax tone generated by the
answering fax machine. The VoIP H.323 call stack then starts a T.38 mode
request using H.245 procedures. If the opposite end of the call acknowledges
the T.38 mode request, the initial audio channel is closed and a T.38 fax relay
channel is opened. When the fax transmission is completed, the call reverts to
voice mode.
AddPac Technology Co.,Ltd.
Company A
Office 1
AP200 VoIP
Gateway
Company B
Office 2
[Figure 5-9] IP Network for T.38 Fax Relay
Gatekeeper
Third-party T.38
Gateway
IP Network
Alternate
Gatekeeper
Company B
Office 1
Gateway
AP200 VoIP
Gateway
Company A
Office 2
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