The theoretical rate at which user data can be transmitted across a circuit. The signaling rate is the total data rate, including overhead, i.e., signaling and control information.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. If the T1 equipment engages in bit robbing, that technique further reduces the transmission rate. If a circuit is used to its maximum capacity, throughput equals the transmission rate. See also bit robbing and throughput.