The examples in Table 1 and Table 2 are the same as the ones in Transcode G.711 to G.729A but in addition to the transcoding G.711 to G.729A, SBC must also transcode between inband DTMF tones on Carrier 1 and DTMF carried in the RTP stream as specified in RFC 2833 on Carrier 2. Since the G711-DEFAULT Codec Entry is set for inband tones (DTMF Relay: None), there are no changes to the Carrier 1 side provisioning.

On the Carrier 2 side, we need to create a modified version of the Codec Entry G729A-DEFAULT with DTMF Relay set to RFC 2833 and use this modified Codec Entry in the PSP on IPTG1 as indicated below. When RFC2833 is selected on the Codec Entry, the DTMF Remove Digits flag is set by default and the DTMF tones are removed from the Carrier 2 audio stream.

Transcode G.711 to G.729A and Convert DTMF PSPs

 

Configuration

Value

Carrier 1 Media G.711 w/Inband DTMF
Gateway Group GWG1 PSP

Carrier 2 Media G.729A w/RFC 2833
DTMF 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 - RFC2833

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

Conditional

Conditional

Codecs Allowed This Leg

G.711A, G.711U

(none selected)

Codecs Allowed Other Leg

(none selected)

G.729

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 Convert DTMF Codec Entries

 

Configuration

Value

G711-DEFAULT

G729A-DEFAULT - RFC2833

Audio Encoding

G.711

G.729A

Fax Tone Treatment

<none>

<none>

Packet Size

10 ms

10 ms

Fax Treatment Failure Handling

Continue

Continue

G.711 Law

Law from other leg

None

Modem Tone Treatment

None

Continue

Modem Treatment Failure Handling

Continue

RFC2833

DTMF Relay

None

Selected

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