Transcode G.711 to G.729A and G.711 to T.38 for Fax

The example in Table 1 and Table 2 is the same as the one in Transcode G.711 to G.729A and Convert DTMF Inband Tones to RFC2833 but in addition to the transcoding G.711 to G.729A, SBCs must also be prepared for fax calls that are handled with G.711 on Carrier 1 and using T.38 (Fax Relay) on Carrier 2. Either SBCs, or Carrier 2 may detect the fax tone and initiate a modification of its media stream that agrees with the Fax Tone Treatment setting in the SBC's Codec Entry.

Transcode G.711 to G.729A and G711 to T.38 for fax

Configuration	Value
Configuration	Carrier 1 Media G.711 w/Fax via G.711 Gateway Group GWG1 PSP	Carrier 2 Media G.729A w/Fax via T.38 IPTG1 PSP
PSP	PSP-Carrier1	PSP-to-Peer
Silence Factor	40	40
Voice Initial Playout Buffer	10	10
TOS	0	184
Data Initial Playout Buffer	50	50
Codec Entry 1	G711-DEFAULT	G729A-DEFAULT - FaxViaT38
Codec Entry 2	<none>	<none>
Codec Entry 3	<none>	<none>
Codec Entry 4	<none>	<none>
AAL Payload Size	47	47
T.38 No. Redundant Packets	1	1
T.38 Low Speed No. Redundant Packets	1	1
T.38 Max Bit Rate	14.4	14.4
Data Rate Mgt Type	Type 2	Type 2
Honor Remote Precedence	Disabled	Disabled
P2P Transcode	Only	Only
Codecs Allowed This Leg	G.711A, G.711U	G.729, T.38
Codecs Allowed Other Leg	(none selected)	(none selected)
RTCP	Not selected	Not selected
Silence Insertion Descriptor	Take defaults	Take defaults
Digit Detect Send Enabled	Not selected	Not selected

Transcode G.711 to G.729A and G.711/T.38 for Fax Codec Entries

Configuration	Value
Configuration	G711-DEFAULT	G729A-DEFAULT FaxViaT38
Audio Encoding	G.711	G.729A
Fax Tone Treatment	<none>	Fax Relay
Packet Size	10 ms	10 ms
Fax Treatment Failure Handling	Continue	Continue
G.711 Law	Law from other leg
Modem Tone Treatment	None	None
Modem Treatment Failure Handling	Continue	Continue
DTMF Relay	None	None

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