Draytek Vigor2820 Series User Manual page 182

Secure Phone
Note: If the incoming or outgoing calls do not match any entry on the phonebook, the router
will try to make the call "being protected". But, if the call ends up "unprotected"(e.g. peer
side does not support ZRTP+SRTP), the router will not play out a warning message.
D i g i t M
D i g i t M
For the convenience of user, this page allows users to edit prefix number for the SIP account
with adding number, stripping number or replacing number. It is used to help user having a
quick and easy way to dial out through VoIP interface.
Enable
Match Prefix
Mode
Vigor2820 Series User's Guide
phone setting.
ZRTP is a cryptographic key-agreement protocol to encrypt
VoIP phone calls to ensure the phone security. It allows users to
encrypt any Session Initiation Protocol (SIP) VoIP voice stream,
as long as the peer side on the call is also using such protocol.
None - If the incoming or outgoing call matches the phone
book entry with secure phone option set to "None", it means the
call should be unprotected.
ZRTP+SRTP – If the incoming or outgoing call matches the
phone book entry with secure phone option set to
"ZRTP+SRTP", it means the call would be protected. A warning
message will be played out if the call ends up unprotected.
a p
a p
Check this box to invoke this setting.
The phone number set here is used to add, strip, or replace the
OP number.
None - No action.
Add - When you choose this mode, the OP number will be
added with the prefix number for calling out through the
specific VoIP interface.
Strip - When you choose this mode, the OP number will be
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