Editing Modified AMI code (section)

==Zero length code suppression <span class="anchor" id="Suppression"></span>==
The first technique used to ensure a minimum density of marks was '''zero code suppression''' a form of [[bit stuffing]], which set the least significant bit of each 8-bit byte transmitted to a 1. (This bit was already unavailable due to [[robbed-bit signaling]].) This avoided the need to modify the AMI code in any way, but limited available data rates to 56,000 bits per second per [[Digital Signal 0|DS0]] voice channel. Also, the low minimum density of ones (12.5%) sometimes led to increased clock [[slip (telecommunication)|slip]]page on the span.

Increased demand for bandwidth, and compatibility with the [[G.703]] and [[ISDN]] [[Primary Rate Interface|PRI]] standards which called for 64,000 bits per second, led to this system being superseded by B8ZS.