3Com VCX V7111 User Manual page 58

Coders
From the Coders screen you can configure the first to fifth preferred coders (and their
corresponding ptimes) for the gateway. The first coder is the highest priority coder and is
used by the gateway whenever possible. If the far end gateway cannot use the coder
assigned as the first coder, the gateway attempts to use the next coder and so forth.
To configure the Gateway's coders, follow these steps:
1
Open the 'Coders' screen (Protocol Management menu > Protocol Definition
submenu > Coders option); the 'Coders' screen is displayed.
Figure 27 Coders Screen
2
From the coder drop-down list, select the coder you want to use. For the full list of
available coders and their corresponding ptimes see
Note: Each coder can appear only once.
3 From the drop-down list to the right of the coder list, select the size of the Voice Packet
(ptime) used with this coder in milliseconds. Selecting the size of the packet determines
how many coder payloads are combined into one RTP (voice) packet.
Note 1: The ptime packetization period depends on the selected coder name.
Note 2: If not specified, the ptime gets a default value.
Note 3: The ptime specifies the maximum packetization time the gateway can receive.
4 Repeat steps 2 and 3 for the second to fifth coders (optional).
5
Click the Submit button to save your changes.
6 To save the changes so they are available after a power fail see
page 145.
Only the ptime of the first coder in the defined coder list is declared in Invite/200 OK SDP,
even if multiple coders are defined.
58
Table 16.
3Com VCX V7111 VoIP SIP Gateway User Manual
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