Aastra 9143i Series Administrator's Manual page 284

IP Phone Administrator Guide
Global SIP Settings
Aastra Web UI
Step Action
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
4-102
to save your changes.
41-001160-03, Rev 00, Releaes 2.4