Bit Stuffing
Bit stuffing is described in detail within the DS3 section. The following white paper has a couple of excellent, detailed examples of how a real-life transmission line service would employ bit-stuffing. The paper is an acrobat file, and the examples start on page 11 with the older M13 Analog DS3 and finish with C-bit Parity DS3 and a fascinating comparison table between the two.