Canopy T1/E1 Multiplexer | September 2004 |
| T1/E1 Multiplexer FPGA Version 3.4 |
For E1 mode, the Canopy T1/E1 Multiplexer supports the following:
◦Transparent support of the E1 channel
◦AMI
◦HDB3
◦up to three ports
Alternate Mark Inversion (AMI)
The template of the
◦1 in 15 Requirement
◦B8ZS.
◦HDB3
The Canopy T1/E1 Multiplexer fulfills the role of a transparent T1/E1 extender. As such, it is compatible with either AMI, B8ZS, or HDB3 coding of signals. The endpoints determine which of the zero suppression techniques will be applied to the signal. The Canopy T1/E1 Multiplexer must be set to match the zero suppression settings at the endpoints of the signal.
The 1 in 15 Requirement (AMI)
The 1 in 15 requirement stipulates that no more than 15 “0s” may be sent be for every “1” that is transmitted. The easiest approach is to make every bit 8 a “1” and to use only the lower 7 bits for data transmission. This 7/8 mode yields a rate of 56 kbps instead of the standard
Configuring the Canopy T1/E1 Multiplexer to AMI accommodates the stipulations for bit handling identified in the 1 in 15 requirement.
Binary Eight Zero Substitution Coding
The limitations imposed by the 1 in 15 requirement led to the development of Binary Eight Zero Substitution (B8ZS) coding. This signal coding technique takes advantage of BPVs in the data stream to be decoded as signal. With B8ZS coding, each block of eight consecutive zeros is replaced with the B8ZS code word. The transmitted bit stream will contain two AMI violations.
Issue 3 | Page 20 of 73 |