Once the SIP Account has been activated, you can use the Domain Name, SIP Username and SIP password to configure your device. DIDForSale all kind of SIP Devices and have been tested with most popular ones, like Cisco, Grandstream, Asterisk, Freepbx, Yealink, Polycom. You can also use Softphones like Grandstream wave, Xlite, Linphone, Zoiper. PS: If you are planning to use softphone, we highly recommend GrandStream Wave, you can download the softphone on IOS and Android.