I’m not sure about the Esemble. Dialers?
The billing software I’m using works independantly from the VoIP box. It is for a callshop application, very simple, DOS based. By the way, I found a cheap VoIP box (4FXS and 4FXO ports) that is able to generate the polarity reversal. Priced under $1,000 US. I am very happy with it.