
Preliminary Data Sheet, Rev. 1
October 2000
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
265
Lucent Technologies Inc.
VT/TU Mapper Functional Description
(continued)
VT/TU Mapper Transmit Path Requirements
(continued)
Pointer Generation
I
The pointer generator will support the following features when operating in asynchronous or bit synchronous
mode:
— If transmit AIS-V is not requested, the following requirements apply:
1. A fixed pointer value of decimal 78 is generated for VT1.5/TU-11 mappings.
2. A fixed pointer value of decimal 105 is generated for VT2/TU-12 mappings.
3. The VT size field will be set to binary 11 for VT1.5/TU-11 mappings.
4. The VT size field will be set to binary 10 for VT2/TU-12 mappings.
5. The new data flag (NDF) set to binary 0110 for VT1.5/VT2 mappings.
6. V3 and V4 is set to the selected overhead default (SMPR_OH_DEFLT (Table 15) in the microprocessor inter-
face block) for all mappings.
— If transmit AIS-V is requested, V1~V4 will be forced to 0xFF.
— Bit stuffing, using the C and S bits, will be performed based on the fullness of the elastic store.
I
The pointer generation will support the following features when operating in byte synchronous mode.
— If transmit AIS-V is not requested, the following requirements apply:
1. The pointer value is generated based on the location of the incoming frame sync for VT1.5/VT2 mappings.
2. The VT size field is set to 11 for VT1.5/TU-11 mappings.
3. The VT size field is set to 10 for VT2/TU-12 mappings.
4. The new data flag (NDF) is set to 0110 for normal VT1.5/VT2 mappings. If a NDF is requested the NDF will
be set to 1001 (binary).
5. If an increment is requested, the pointer bytes, V1 and V2, are programmed with the I-bits inverted. The
pointer action byte, V3, will be programmed to the selected default (microprocessor bit
SMPR_FXD_STFF_DEFLT (Table 15)) as well as the byte directly following V3. However, when incrementing
from 139 to 0 for VT2 mapping, the pointer generator sends out NDF-V indication with the correct pointer (0)
instead of the increment indication.
6. If a decrement is requested, the pointer bytes, V1 and V2, will be programmed with the D bits inverted. The
pointer action byte, V3, will be programmed to actual customer data. However, when decrementing from 0 to
139 for VT2 mapping, the pointer generator sends out NDF-V indication with the correct pointer (139) instead
of the decrement indication.
7. The V4 byte will be programmed to the selected overhead default (microprocessor bit SMPR_OH_DEFLT) for
all mappings.
— If transmit AIS-V is requested, V1~V4 will be forced to 0xFF.