3Com VCX v7111 User Manual page 84

•
Each coder can appear only once.
•
If not specified, the ptime gets a default value. The ptime specifies packetization
time the gateway expects to receive. The gateway always uses the ptime
requested by the remote side for sending RTP packets. Only the ptime of the
first coder in the list is declared in INVITE / 200 OK SDP, even if multiple coders
are defined.
•
If payload type is not specified, a default is used.
•
For G.729 it is also possible to select silence suppression without adaptations
•
If coder G.729 is selected and silence suppression disabled, the gateway
includes the string 'annexb=no' in the SDP of the relevant SIP messages. If
silence suppression is enabled or set to 'Enable w/o Adaptations', 'annexb=yes'
is included.
Supported Coders and their Attributes
Table 20
Coder Name Packetization Time
G.711 A-law 10, 20 (default), 30, 40,
[g711Alaw64k]
50, 60, 80, 100, 120
G.711 μ-law
10, 20 (default), 30, 40,
[g711Ulaw64k] 50, 60, 80, 100, 120
G.729 10, 20 (default), 30, 40,
[g729] 50, 60
G.723.1
30 (default), 60, 90
[g7231]
G.726 10, 20 (default), 30, 40,
[g726]
50, 60, 80, 100, 120
T.38
[t38fax]
G.711A-law_VBD 10, 20 (default), 30, 40, 50,
[g711AlawVbd] 60, 80, 100, 120
G.711U-law_VBD 10, 20 (default), 30, 40, 50,
[g711UlawVbd] 60, 80, 100, 120
Transparent N/A.
84
Rate
Always 64
Always 64
Always 8
5.3 [0], 6.3 [1]
(default)
16 [0], 24 [1],
32 [2]
(default), 40
[3]
N/A N/A
Always 64
Always 64
Payload
Type
Always 8
Always 0
Always 18
Always 4
Dynamic (0-
120)
N/A
Dynamic (0-
120)
Dynamic (0-
120)
®
3Com VCX V7111 VoIP Gateway User Guide
Silence Suppression
Disable [0]
Enable [1]
Disable [0]
Enable [1]
Disable [0]
Enable [1]
Enable w/o Adaptations
[2]
Disable [0]
Enable [1]
Disable [0]
Enable [1]
N/A
N/A
N/A