In
telecommunications, in-band signaling is the sending of
metadata and
control information in the same band, on the same channel, as used for data.For example, when dialing a modern
telephone, the telephone number is encoded and transmitted across the telephone line as Dual-Tone Multi-Frequency (
DTMF) tones. The tones "control" the telephone system by instructing the telephone company's
equipment where to route the call to. These control tones are sent over the same
channel and in the same band (300Hz to 3.4kHz) as the voice and other sounds of the telephone call. In-band signalling is also used on older telephone carrier systems to provide
inter-exchange information on how to route calls. Examples of this kind of in-band signalling system are
SS5 and
R2.
See more at Wikipedia.org...
<
communications> (bit-robbing) The exchange of call control information on the same channel as the telephone call or data transmission. Since one bit in a frame is periodically used for signalling instead of data, this is often referred to as
bit robbing.
This is the reason why a
D1 channel in the T-carrier system can only carry 56 Kbps of usable data instead of the 64 Kbps carried by the
D0 channel in the E-carrier system.
(2000-03-10)
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