TXC-04252AIPQ Transwitch Corporation, TXC-04252AIPQ Datasheet - Page 68

• Manufacturer Part Number: TXC-04252AIPQ
• Manufacturer: Transwitch Corporation

Specifications of TXC-04252AIPQ

• Pin Count: 160
• Screening Level: Industrial
• Package Type: PQFP
• Lead Free Status / Rohs Status: Not Compliant

Ed. 3, December 2000
QE1M
TXC-04252
TXC-04252-MB
N2 (Z6) Overhead Byte (Tandem Connection)
The Tandem Connection feature is enabled for a TU/VT by writing a 1 to control bit TCnEN, when control bit
J2nSIZE is a 0. When control bit TCnEN is written with a 0, the tandem connection feature is disabled. See
address 051H, bit 4, in the Memory Map Descriptions section for more detail on TCnEN. The bit placement in a
received N2 (Z6) byte is as shown below:
BIP-2, AIS INDICATION, TC REI AND TC OEI PROCESSING
One or two errors may be detected in the TC BIP-2 comparison, and they are counted individually in an 8-bit
counter when control bit BLOCK is written with a 0 (An TC BIP-2 Error Counter, Bn TC BIP-2 Error Counter).
When control bit BLOCK is written with a 1, one or two parity errors are counted as a single block error.
A tandem connection AIS alarm (AnTCAIS, BnTCAIS) is declared when bit 4 is equal to 1 for five consecutive
frames. Recovery occurs when bit 4 is equal to 0 for five consecutive frames.
An 8-bit counter (An TC REI Counter, Bn TC REI Counter) is provided for counting the number of REI bits
received as equal to 1 in bit 5 (TC REI) in the N2 (Z6) byte. A REI indication (a 1) indicates that the distant end
has detected one or two errors when the BIP-2 calculated for frame f-1 (all the bytes) is compared against the
BIP-2 value carried in the N2 (Z6) byte in frame f.
An 8-bit counter (An TC OEI Counter, Bn TC OEI Counter) is provided for counting the number of OEI bits
received as equal to 1 in bit 6 (TC OEI) in the N2 (Z6) byte. An OEI indication (a 1) indicates that the distant
end has detected one or two errors when the BIP-2 calculated for frame f-1 is compared against the BIP-2
value carried in the V5 byte in frame f.
Bits 7 and 8
A multiframe alignment pattern, trace identifier message, TC RDI and TC ODI indications are assigned to bits
7 and 8 in the frames of a 76-frame structure, as shown below:
Bit
21 - 24 thru 61 - 64 TC Trace ID Bytes No. 3 thru 13
Proprietary TranSwitch Corporation Information for use Solely by its Customers.
Frame No.
1
13 - 16
17 - 20
65 - 68
69 - 72
9 - 12
1 - 8
73
74
75
76
BIP-2
2
Frame Alignment, 1111 1111 1111 1110
TC Trace ID Byte No. 0 (1 C1 C2 C3 C4 C5 C6 C7)
TC Trace ID Byte No. 1 (0 X X X X X X X)
TC Trace ID Byte No. 2 (0 X X X X X X X)
TC Trace ID Byte No. 14 (0 X X X X X X X)
TC Trace ID Byte No. 15 (0 X X X X X X X)
Bit 7 = 0, Bit 8 = TC RDI
Bit 7 = TC ODI, Bit 8 = 0
Bit 7 = 0, Bit 8 = 0
Bit 7 = 0, Bit 8 = 0
DATA SHEET
3
1
- 68 of 148 -
Indication
AIS
N2 (Z6) Byte Definition
4
REI
TC
5
TC OEI
(FEBE)
6
7
TC RDI/ODI
Trace ID
8