Modified AMI Code - Zero Code Suppression

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 DS0 voice channel. Also, the low minimum density of ones (12.5%) sometimes led to increased clock slippage on the span.

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compatibility with the G.703 and ISDN PRI standards which called for 64,000 bits per second, led to this system being superseded by B8ZS.

Read more about this topic:  Modified AMI Code

Famous quotes containing the words suppression and/or code:

    Fashion required the suppression of all naturalness—’to walk upright, with unbending joints; to shake hands after the pump- handle formula; to look inexpressibly indifferent towards everybody and everything; and speak only in a mincing voice was to be a decorous member of society.’
    —For the State of Rhode Island, U.S. public relief program (1935-1943)

    Hollywood keeps before its child audiences a string of glorified young heroes, everyone of whom is an unhesitating and violent Anarchist. His one answer to everything that annoys him or disparages his country or his parents or his young lady or his personal code of manly conduct is to give the offender a “sock” in the jaw.... My observation leads me to believe that it is not the virtuous people who are good at socking jaws.
    George Bernard Shaw (1856–1950)