A device optioned for B8ZS (Bipolar 8-Zero Substitution) inserts a bipolar violation into any frame containing 8 zeroes in a specific sequence during transmission of that frame. The device at the receiving end simply looks for that specific sequence and changes the bit sequence in that frame back to 8 zeros.
they just work they just work,work,work
the work a machine does is the work outputwhat it takes to do the work is the work inputSources;The_work_that_the_simple_machine_does_is_called_the_work
the work a machine does is the work output what it takes to do the work is the work input
The work done by a machine is called work output
work output
AMI and B8ZS
+000+-0-+
B8ZS
No, E1's use HDB3 instead. HDB3 stands for High Density Bipolar of order 3. In principle, it works in a similar way to B8ZS coding, but substitutes specific bipolar violation patterns to replace any instance of 4 consecutive zero bits (whereas B8ZS uses a specific BPV pattern in place of a frame containing 8 zeros).
+-000+-0-+00+00
They are AMI (Alternate Mark Inversion) and B8ZS (Bi-polar with 8-Zero Substitution)
A device optioned for B8ZS (Bipolar 8-Zero Substitution) inserts a bipolar violation into any frame containing 8 zeroes in a specific sequence during transmission of that frame. The device at the receiving end simply looks for that specific sequence and changes the bit sequence in that frame back to 8 zeros. For a more complete understanding, it's important to also understand Alternate Mark Inversion (AMI) Line Coding and what a Bipolar Violation means. AMI Line Coding means that each digital '1' bit (also referred to as a 'Mark') uses alternating positive and negative voltage pulses to represent those bits, even if those '1' bits are separated by '0' bits. A Bipolar Violation is when two consecutive '1' bits voilate that AMI rule. Since a DS1 signal depends on a certain level of 1's density to maintain receive synchronization, long strings of '0's can cause timing slips. To prevent this, when a frame containing 8 zero's is transmitted, B8ZS changes bits 4, 5, 7 and 8 into 1's, but bits 5 and 7 will either both be positive or both negative, causing the specific bipolar violation that a receiving device optioned for B8ZS is looking for, and it will change those four bits back to 0's. One other point - B8ZS only comes into play when an 8-bit frame containing all 0's occurs. So, B8ZS isn't really different from AMI, it's more like an enhancement to AMI, with a special condition that only occurs when an all-0's frame is encountered.
uni-polar, bi-polar, rz, nrz, ami, b8zs, b3zs, 2b/1q, manchester, differential manchester, 4b/5b
the line coding can be either AMI or B8ZS according to how the equipment is set up along the path and at either end.
B8ZS (Bipolar 8-Zero Substitution) Line Coding is used as a technique to maintain 1's density in telecommunications. It isn't really used for scrambling, though it does change specific bits to insert a bipolar violation when a frame of 8 consecutive 0's is transmitted. B8ZS is typically used on DS1 signals, and has become the standard line coding option for most modern telecom equipment involving T1 circuits. Equipment using DS1 signalling depends on a certain number of 1's (referred to as 1's density) to maintain synchronization, since the timing circuits will often derive clocking based on the rising voltage of a digital '1' pulse. Since a digital 0 is represented by a lack of a pulse, the receiving device cannot use 0's to help maintain clocking. A device optioned for B8ZS replaces a frame of eight 0's with one containing four 1's in a specific pattern, including a bipolar violation, which a receiving device (also optioned for B8ZS) will recognize, and will then translate that frame back into eight 0's. But this also helps maintain timing between those devices, due to the 1's being transmitted instead of all zero's.
A device optioned for B8ZS (Bipolar 8-Zero Substitution) inserts a bipolar violation into any frame containing 8 zeroes in a specific sequence during transmission of that frame. The device at the receiving end simply looks for that specific sequence and changes the bit sequence in that frame back to 8 zeros. For a more complete understanding, it's important to also understand Alternate Mark Inversion (AMI) Line Coding and what a Bipolar Violation means. AMI Line Coding means that each digital '1' bit (also referred to as a 'Mark') uses alternating positive and negative voltage pulses to represent those bits, even if those '1' bits are separated by '0' bits. A Bipolar Violation is when two consecutive '1' bits voilate that AMI rule. Since a DS1 signal depends on a certain level of 1's density to maintain receive synchronization, long strings of '0's can cause timing slips. To prevent this, when a frame containing 8 zero's is transmitted, B8ZS changes bits 4, 5, 7 and 8 into 1's, but bits 5 and 7 will either both be positive or both negative, causing the specific bipolar violation that a receiving device optioned for B8ZS is looking for, and it will change those four bits back to 0's. One other point - B8ZS only comes into play when an 8-bit frame containing all 0's occurs. So, B8ZS isn't really different from AMI, it's more like an enhancement to AMI, with a special condition that only occurs when an all-0's frame is encountered.
There are a number of different encoding methods used on T1 lines. Alternate Mark Inversion (AMI), Bipolar With 8-Bit Substitution (B8ZS), and High Density Bipolar Three Code (HDB3).