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XRT86VL38
PRELIMINARY
xr
OCTAL T1/E1/J1 FRAMER/LIU COMBO
REV. P1.0.6
329
5.9
Transmit SLC®96 Data link Controller
The SLC®96 T1 format is invented by AT&T and is used between the Digital Switch and a SLC®96 formatted
remote terminal. The purpose of the SLC®96 product is to provide standard telephone service or Plain Old
Telephone Service (POTS) in areas of high subscriber density but back-haul the traffic over T1 facilities.
To support the SLC®96 formatted remote terminal equipment, which is likely in an underground location, the
T1 framer must:
•
Indicate equipment failures of the equipment to maintenance personal
•
Indicate failures of the POTS lines
•
Test the POTS lines
•
Provide redundancy on the T1s
The SLC®96 framing format is a D4 Super-frame (SF) format with specialized data link information bits. These
data link information bits take the position of the Super-frame Alignment (Fs) bit positions. These bits consist of
the following.
•
Concentrator bits (C, bit position 1 to 11)
•
First Spoiler bits (FS, bit position 12 to 14)
•
Maintenance bits (M, bit position 15 to 17)
•
Alarm bits (A, bit position 18 to 19)
•
Protection Line Switch bits (S, bit position 20 to 23)
•
Second Spoiler bit (SS, bit position 24)
•
Resynchronization pattern (000111000111)
In SLC®96 mode, a six 6-bit datalink message will generate a one 9-ms frame of the SLC®96 message
format. The format of the datalink message is given in BELLCORE TR-TSY-000008. When SLC®96 mode is
enabled, the Fs bit is replaced by the data link message read from memory at the beginning of each D4 super-
frame. The XRT86VL38 allocates two 6-byte buffers to provide the SLC®96 Data Link Controller an alternating
access mechanism for information transmission. The bit ordering and usage is shown in the following table;
and the LSB is sent first. Note that these registers are memory-based storage and they need to be initialized.
Each register is read out of memory once every six SF super-frames. The memory holding these registers
owns a shared memory structure that is used by multiple devices. These include DS1 transmit module, DS1
receive module, Transmit LAPD Controller, Transmit SLC®96 Data Link controller, Bit-Oriented Signaling
Processor, Receive LAPD Controller, Receive SLC®96 Data Link Controller, Receive Bit-Oriented Signaling
Processor and microprocessor interface module.
B
YTE
5
4
3
2
1
0
1
0
1
1
1
0
0
2
C1
1
1
1
0
0
3
C7
C6
C5
C4
C3
C2
4
1
0
C11
C10
C9
C8
5
A2
A1
M3
M2
M1
0
6
0
1
S4
S3
S2
S1