- In a telephone circuit, the transmission of control signals, such as dial tones and busy signals, via the same channel utilized for voice transmission. This contrasts with out-of-band signaling, in which a separate channel is used.
- In data transmission, signaling in which the least significant bit is taken from the information stream and utilized for control signals and other overhead. Sometimes used over T1 or E1 lines. Also called robbed-bit signaling, or bit robbing.