TXC-04222-AIOG Transwitch Corporation, TXC-04222-AIOG Datasheet - Page 77

• Manufacturer Part Number: TXC-04222-AIOG
• Manufacturer: Transwitch Corporation

Specifications of TXC-04222-AIOG

• Screening Level: Industrial
• Package Type: BGA
• Lead Free Status / Rohs Status: Not Compliant

TRANSMIT CROSS MAPPING APPLICATIONS
The TEMx28 supports cross mapping applications in which a DS1 format is carried in a VC-12 for transport by
a VT2/TU-12. The options associated with this feature are given in the following table. The cross mapping fea-
ture control in the add direction is independent of the drop direction. Please note: the cross connect feature will
not be supported when the VT/TU interface for channel n is selected.
OVERHEAD BYTE INSERTION
In general, the transmitted overhead byte states (V5, J2, N2, and K4 bytes) for each channel may be controlled
by internal alarm states, or by the microprocessor.
V5 Byte
The placement of bits with in the V5 byte is shown below.
BIP-2
Bits 1 and 2 in the V5 byte carry a Bit Interleaved Parity - 2 (BIP-2). Bit 1 is set so that the parity of all odd num-
bered bits (1, 3, 5, and 7) in all the bytes in the previous VC-11/VC-12 is even, while bit 2 is set similarly for all
even numbered bits.
The calculation includes all of the payload and overhead bytes, but excludes the V1, V2, V3 and the V4 bytes.
BIP-2 errors can be transmitted by setting control bit ATnFB2 (bit 3, register X+064H) or BTnFB2 (bit 3, regis-
ter X+0D4H) for the A and B side add buses respectively.
Remote Error Indication Bit
Bit 3 carries a remote error indication (REI). This bit carries the block error indication from the incoming BIP-2
comparison performed in the drop direction for the VT/TU selected for channel n. The TEMx28 provides a syn-
chronization circuit between the dropped TU/VT and the added TU/VT to prevent lost counts due to differences
in clock phases between the drop and add sides. Single REI can be transmitted by setting control bit ATnFFB
(bit 6, register X+065H) or BTnFFB (bit 6, register X+0D5H) for the A and B side add buses respectively.
Remote Failure Indication
The transmit remote failure indication for the VT/TU selected is controlled by control bit ATnRFI (bit 7, X+064H)
or BTnRFI (bit 7, X+0D4H) for the A and B side add buses respectively. When control ATnRFI or BTnRFI is set
to 1, bit 4 in the V5 byte is transmitted as a 1.
VT/TU Select Register
X+01AH, 08AH
Bit
A/B Add
Bit 7
0
0
1
1
MSB
Proprietary TranSwitch Corporation Information for use Solely by its Customers
1
BIP-2
(bit 4, X+002H)
TnE1SL
2
0
1
0
1
REI
DS1 Asynchronous format mapped to a VT1.5/TU-11.
Not used.
Cross Mapping. DS1 Asynchronous format mapped to a VT2/TU-12.
E1 Asynchronous format mapped to a VT2/TU-12.
3
DATA SHEET
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RFI
4
5
Operation
Signal Label
6
7
TXC-04222-MB, Ed. 6
TXC-04222
TEMx28
RDI
June 2003
8
LSB