1. To enter the phone's web interface enter device's IP-address in URL bar.
To attain the phone's IP address, press the "Menu" button (Page) and select "Network" => "CurrentIP"
Open "Voice" tab "SIP" and specify range of RTP ports.
RTP Port Min: 1024
RTP Port Max: 65536
To save changes click Submit All Changes
2. Open "Voice" tab Ext1 and enter the following data:
Proxy: sip.zadarma.com
Proxy: pbx.zadarma.com
Register Expires: 300
Display Name: Your sip number (for example 111111) from personal account
UserID: Your sip number (for example 111111) from personal account
Password: Your password of sip number, from "SIP Connection" in personal account.
Display Name: Your internal PBX number (for example 1234-100) from personal account
UserID: Your internal PBX number (for example 1234-100) from personal account
Password: Your password of internal PBX number from personal account
To save changes click Submit All Changes