Zoiper - QR Code
Zoiper offers a remote QR code generation feature, so in the MAC template section you need to activate the QR code generation and to enter the URL used to generate the QR code, like:
https://oem.zoiper.com/qr.php?provider_id=ce66c3c73142b5943351bd4918e1cccf&u={$username}&h=&p={$secret}&o=&t=&x=&a=&tr=