User friendly interface
supports SIP for signalling.
supports G729, GSM and [url removed, login to view] codec for sending audio data.
Can run behind NAT or on private IP.
Should run on application layer so it supports GPRS, WiFi and Bluetooth for internet connectivity.
This software will run on the phone having Symbian or Windows Mobile 5 and 6.
fully customizable Interface
client does not need to configure anything else, except inputting PIN of their account.
Should be able to use with any kind of Soft switch which support SIP