Aastra Telecom 55I User Manual

Global SIP Settings

41-001160-00, Release 2.1, Rev 04

4-73

Configuring Network and Session Initiation Protocol (SIP) Features

5

Enter a "Customized Codec Preference List". For example, 

Valid values are:

For this parameter, you specify a customized codec list which allows you to use the preferred Codecs 
for this IP phone. Default for the “Customized Codec Preference List” is blank.

6

Select a method to use from the “DTMF Method” list box. Valid values are RTP, SIP Info, Both. 
Default is RTP.

Note: You can configure the DTMF Method on a global or per-line basis.

7

Select the type of RTP encryption to use from the “RTP Encryption” list box. Valid values are SRTP 
Disabled, SRTP Preferred, or SRTP Only. Default is SRTP Disabled.

Note: You can configure RTP Encryption on a global or per-line basis.

8

The  “Silence Suppression” field is enabled by default. Disable this field by unchecking the check 
box.

When enabled, the phone negotiates whether or not to use silence suppression. Disabling this 
feature forces the phone to ignore any negotiated value.

9

Click 

 to save your changes.

payload

0 for G.711 u-Law
8 for G.711 a-Law
18 for G.729a

ptime (in milliseconds)

5, 10, 15, 20.....90

silsupp

on

off