We mainly replace old telephony equipment. If, for instance, there is an old Alcatel telephone system (digital or analog), and the customer asks us for a new option for IP telephony, then we offer both the Cisco- and Asterisk-based systems. We know the billing, we know the pricing of the items and what we can offer with both solutions.

There are multiple factors involved when selecting a vendor

• stability
• support
• features. 

If the product is stable, the product has good support, and it has enough features which we can offer to our clients, then the product is under our consideration.

Yes I used to use the Traditional Analog EPABX. Switched to Asterisk to make use of more advanced features and the above mentioned reasons.