TFRA08C13-DB AGERE [Agere Systems], TFRA08C13-DB Datasheet - Page 32

• Manufacturer Part Number: TFRA08C13-DB
• Description: TFRA08C13 OCTAL T1/E1 Framer
• Manufacturer: AGERE [Agere Systems]

TFRA08C13 OCTAL T1/E1 Framer
LIU-Framer Interface
The receive framer indicates a bipolar violation upon detecting a block of 15 consecutive 0s with no AMI encoding
(no pulses on either RPD or RND). When an internal bipolar violation and a violation of 15 consecutive 0s occur
simultaneously, only one violation is indicated.
Table 4. DS1 ZCS Encoding
DS1: Binary 8 Zero Code Suppression (B8ZS)
Clear channel transmission can be accomplished using binary 8 zero code suppression (B8ZS). Eight consecutive
0s are replaced with the B8ZS code. This code consists of two bipolar violations in bit position 4 and 7 and valid
bipolar marks in bit positions 5 and 8. The receiving end recognizes this code and replaces it with the original string
of eight 0s.
The receive framer indicates excessive zeros upon detecting a block of eight or more consecutive 0s. (no pulses on
either RPD or RND). Both excessive zeros and coding violations are indicated as bipolar violations.
Table 5 shows the encoding of a string of 0s using B8ZS. B8ZS is recommended when ESF format is used. V rep-
resents a violation of the bipolar rule and B represents an inserted pulse conforming to the AMI rule.
Table 5. DS1 B8ZS Encoding
* Bits 5—6 represent a bipolar violation pair. Bipolar violation with respect to the last previous 1 bit.
32
Before B8ZS
After B8ZS*
ZCS Data (Framer Mode)
Bit Positions
Input Bit Stream
Default ZCS
1
0
0
2
0
0
(continued)
3
0
0
00000000
00000010
00000010
V
4
0
B
5
0
6
0
0
01010000
01010010
01010000
V
7
0
B
8
0
—
B
1
—
(data time slot remains clear)
0
0
—
B
1
1
0
0
00000000
00000010
00000000
2
0
0
Preliminary Data Sheet
3
0
0
Lucent Technologies Inc.
V
4
0
Lucent Technologies Inc.
5
0
B
October 2000
6
0
0
00000000
00000010
00000010
V
7
0
B
8
0