76 V7122 GatewayUser GuideIf not specified, the ptime gets a default value.The ptime specifies the packetization time the gateway expects to receive.The gateway always uses the ptime requested by the remote side for sendingRTP packets.4 From the Rate drop-down list, select the bit rate (in kbps) for the coder you selected.5 In the Payload Type field, if the payload type for the coder you selected is dynamic, entera value from 0 to 120 (payload types of ‘well-known’ coders cannot be modified).The payload type identifies the format of the RTP payload.If not specified, a default is used.6 From the Silence Suppression drop-down list, enable or disable the silence suppressionoption for the coder you selected.For G.729 it is also possible to select silence suppression without adaptations.7 Repeat Steps 2 to 6 for the second to fifth coders (optional).8 Click the Submit button to save your changes.9 To save the changes so they are available after a power fail, see Saving Configuration.Only the ptime of the first coder in the defined coder list is declared in INVITE / 200OK SDP, even if multiple coders are defined.If the coder G.729 is selected and silence suppression is enabled (for this coder),the gateway includes the string ‘annexb=no’ in the SDP of the relevant SIPmessages. If silence suppression is set to ‘Enable w/o Adaptations’, ‘annexb=yes’is included.Advanced Parameters Use this submenu to configure the following gateway’s advanced control protocolparameters: CDR and Debug Miscellaneous Parameters Supplementary ServicesNumber Manipulation TablesThe VoIP gateway provides four Number Manipulation tables for incoming and outgoingcalls. These tables are used to modify the destination and source telephone numbers so thatthe calls can be routed correctly.
