We need softphone client with encryption
Need these features.
Softphone with G.729 codec
Codec Supported Microsoft G723.1/G711
Call timer
Display Balance
Countdown call timer
Last Number Redial
Local signaling (Dial tone, busy, ring back, etc.) for user comfort
Touch Tone
Address Book
phone-2-phone
Sms support
call History
Microsoft Outlook Sync with Address Book
Micro Phone Volume Control
Speaker Volume Control
Speaker and Volume Progress bar
Small application
Work with any full-duplex sound card
UPNP NAT/Firewall support, stable SIP RTP ports
Auto-configuration of settings for easy deployment
Configuration Wizard
DNS support