[1] Retail customers of an ITSP may use traditional analog telephone sets attached to an analog telephony adapter (ATA) to connect to the service provider's network via a local area network, they may use an IP phone, or they may connect a private branch exchange (PBX) system to the service via media gateways.
[citation needed] In the United States, net2Phone began offering consumer VoIP service in 1995.
[2] Usually, ITSPs negotiate agreements for route termination to various parts of the world from multiple VoIP providers.
Customers may be able to do this by specifying the maximum price they are willing to pay per minute for a call and the lowest quality they are willing to tolerate.
The ITSP routing software searches for the wholesale VoIP providers who meet the customer specification and attempt to route the customer call to the providers starting with the one have the lowest quoted price.