Pret A Manger already had a company-wide virtual private network, mainly built on DSL lines, to carry data. It brought in Redstone Communications to convert the existing lines to allow them to carry free "packetised" voice calls with the help of IP converters.
Without converters, users can make voice calls over a shared DSL line, but the voice calls go over the public switched telephone network, accruing extra costs.
Calls from the shops are routed through the private branch exchange at Pret A Manger's head office , which has been equipped with Cisco's Call Manager system to cope with the packetised calls. The shops are using standard phones to make the calls.
Pret A Manger's IT director Andrew Walker said, "We now have a cost-effective solution that enables us to centralise resources, work well as a team and keep overheads under control."