bit robbing

Bit robbing is not the same as bit stuffing.

Bit robbing is a technique used in signaling on the T-carrier system, the widely-used system for transmitting both voice and data in digital form in the public switched telephone network (PSTN) and in private networks. In the basic T-1 system, a 193 bit frame, serving 24 channels, is transmitted in a sequence of 12 frames that are referred to as a superframe. Special signaling information, such as whether a voice channel is on-hook or off-hook, is included within the superframe by using a bit (called the  a bit) that is "robbed" from the sixth frame as a signaling bit and another bit (the b bit) that is robbed from the 12th frame.

Bit robbing is acceptable for voice conversations or data transmissions that are received by a modem but not for "pure" data transmission (where every bit is significant). Bit robbing is the reason that a 64 Kbps channel only carries 56 Kbps of usable data. Bit robbing is a form of in-band signalling.

This was last updated in April 2005

Dig Deeper on Network Administration

Start the conversation

Send me notifications when other members comment.

By submitting you agree to receive email from TechTarget and its partners. If you reside outside of the United States, you consent to having your personal data transferred to and processed in the United States. Privacy

Please create a username to comment.


File Extensions and File Formats

Powered by: