voip

• Asterisk
• https://www.freepbx.org – Graohical frontend for Asterisk
• https://freeswitch.com
• https://www.vicidial.com
• https://www.linphone.org
• https://vitalpbx.org
• https://www.opensips.org

VoIP Billing Software

• ASTPP

VoIP Providers

• https://voip.ms
• https://sip.telnyx.com