An amazing Gadget - The Huawei HG556a ADSL/3g Home Gateway.1. Setup BSNL ADSL in PPoE Mode:Logon to the webinterface - Most are configured for 192.168.1.1 and some to 192.168.0.1 - figure this out by enabling DHCP in your network card and see the gateway IP using ipconfig/ifconfig.Use admin user and password is normally provided in the user manual.AdvancedSetup->WAN->ADSL Uplink-> Remove all existing interfaces.Add a new interface - VPI-0, VCI - 35, Service Category - UBR without PCR-> NextSelect PPPoE and LLC/Snap Bridging encapsulation mode -> NextPPPUserName: BSNL Provided usernamePPPPassword: BSNL provided passwordDont change anything else on this page. -> NextService Name - Data/Voice if you want to use this interface for both Data and VOIP or else only Data.Save and Reboot. You should now be connected to BSNL ADSL.2. Setup BSNL/Airtel 3GAdvancedSetup->WAN->USB Uplink - Dont change anything->NextNetwork type - 3G preferred or any other based on your choice.Network - Autosearch and register -> Enable Wan-> Nextsave and rebootSet your 3G backup mode in Advanced Setup->3G backup.3. VOIP/SIP Setting - (I use callcentric - use your VOIP details)From the Web InterfaceVOICE > SIP Server->PrimaryServerSIP Proxy Server Address: callcentric.comSIP Proxy Server Port: 5060SIP Registrar Server Address: callcentric.comSIP Registrat Server Port: 5060SIP Service Domain: callcentric.comSIPID/USername - Your Callcentric ID 17777numberPassword - your password.Dont change any other option in this page.SIP Advanced - Select your PPPoE interface from the Interface name list that has the voice service- should be something like ppp_0_35_1-PPPoE.No other changes required in this page. Enable SIP1 in SIP UserSave (Dont Reboot yet)Telnet to your terminalTelneto 192.168.0.1User and passwordtype voice set all enablesaveGo back to the web page and save & reboot to commit changes.4. DynDNS.org -1. Go into your terminal's webpage-> AdvancedSetup->DNS->DynamicDNS-> Remove all the Services.Save&RebootTelnet to your Terminaltype ifconfig to identify the PPTP interface type - ddns add --username --password --interface ppp_0_35_1 --service dyndnstype - ddns show to confirm only what you added shows up.SaveReboot.5. Connect your USB data storage and ftp/share given in manualDLNA Server can be enabled and reached via - 192.168.0.1:9000regards.