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STANDARD PRODUCT
PM4351 COMET
DATA SHEET
PMC-1970624
ISSUE 10
COMBINED E1/T1 TRANSCEIVER
PROPRIETARY AND CONFIDENTIAL
263
Register 087H: E1 TRAN National Bits Codeword
Bit
Type
Function
Default
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
SaX_EN[1]
SaX_EN[2]
SaX_EN[3]
SaX_EN[4]
SaX[1]
SaX[2]
SaX[3]
SaX[4]
0
0
0
0
1
1
1
1
When the E1/T1B bit of the Global Configuration register is a logic 0, this register
is held reset.
SaX[1:4]:
The code word SaX[1:4], (where X = 4, 5, 6, 7 or 8 as selected by the
SaSEL[2:0] bits in the E1 TRAN National Bits Codeword Select register)
appears in bit X (where X= 4, 5, 6, 7 or 8 as selected by the SaSEL[2:0] bits)
of TS0 in frames 1, 3, 5 and 7 respectively (SMF I), or in frames 9, 11, 13 and
15 respectively (SMF II) of a G.704 CRC-4 multiframe. If X = 4, Sa4[1:4] bits
appear in bit 4 of frames 1, 3, 5, and 7 respectively (SMF I) or in bit 4 of
frames 9, 11, 13, and 15 (SMF II) of a G.704 CRC-4 multiframe. If X = 8, the
codeword is inserted into bit 8 of TS 0 in frames 1, 3, 5 and 7 respectively
(SMF I), or in frames 9, 11, 13 and 15 respectively (SMF II) of a G.704 CRC-4
multiframe.
The code word written in bits SaX[1:4] is latched internally and is updated
every submultiframe. Therefore, if the code word is written into register 7
during SMF I of a G.704 CRC-4 multiframe, it will appear in the SaX[1:4] bits
of SMF II of the same multiframe. If the code word is written into register 7
during SMF II of a multiframe, its contents will be latched internally and will
appear in SMF I of the next multiframe.
Hence, a code written in SMF I of a multiframe is latched internally and
appears in bit positions 4, 5, 6, 7, or 8 of TS0 in frames 9, 11, 13, and 15 of
the CRC-4 multiframe. Also, a code word written during SMF II of a G.704
CRC-4 multiframe will appear in bit positions 4, 5, 6, 7, or 8 of TS0 in frames
1, 3, 5 and 7 of the subsequent CRC-4 multiframe.