The total rate at which data, including overhead, i.e., signaling and control information, can be sent across a circuit.That compares with the transmission rate, which is the theoretical rate at which user data can be transmitted across a circuit.Therefore, the transmission rate is always less than the signaling rate. For example, a typical T1 circuit has a signaling rate of 1.544 Mbps, but a transmission rate of only 1.536 Mbps, as 0.008 Mbps is required for overhead. See also circuit, data, overhead, signaling and control, and transmission rate.