Ringtone BD Android App - playslack.com , "Ringtone BD" can be used on the compatible Android phone sets to make VoIP calls using a service provider. It allows international voice calls over WiFi or 3G/4G network. Service provider who bundled this application with their services can offer their customers to download Ringtone BD Dialer. After install, user needs username and password. Please contact your reseller to get access PIN.