Call Rounding
Indicates how the length of a call is determined for billing purposes. This is usually expressed in terms of the minimum billing period and the billing increment. For example, 30/6 means that all calls will be billed for a minimum of 30 seconds, with calls that are longer than 30 seconds billed in 6 second increments.

Dedicated Service
A type of service that requires a direct connection between your phone system and a long distance carrier. It is designed for high-volume users.

Inbound Service
Another term for toll free service. Most carriers use the term "inbound" to indicate that the recipient actually pays for "toll free" calls.

Switched Service
A type of service that routes toll free numbers into your phone system through regular phone lines.