tfra08c13 ETC-unknow, tfra08c13 Datasheet - Page 41

• Manufacturer Part Number: tfra08c13
• Description: Tfra08c13 Octal T1/e1 Framer
• Manufacturer: ETC-unknow

Preliminary Data Sheet
October 2000
Lucent Technologies Inc.
Lucent Technologies Inc.
Frame Formats
Cyclic redundancy checking is performed over the entire ESF data payload (4,608 data bits, with all 24 framing bits
(F
The ESF remote frame alarm consists of a repeated eight ones followed by eight 0s transmitted in the data link
position of the framing bits.
T1 Loss of Frame Alignment (LFA)
Loss of frame alignment condition for the superframe or the extended superframe formats is caused by the inability
of the receive framer to maintain the proper sequence of frame bits. The number of errored framing bits required to
detect a loss of frame alignment is given is Table 14.
Table 14. T1 Loss of Frame Alignment Criteria
The receive framer indicates the loss of frame and superframe conditions by setting the LFA and LSFA bits
(FRM_SR1 bit 0 and bit 1), respectively, in the status registers for the duration of the conditions. The local system
may give indication of its LFA state to the remote end by transmitting a remote frame alarm (RFA). In addition, in
the LFA state, the system may transmit an alarm indication signal (AIS) to the system interface.
D4
SLC -96
DDS: Frame
ESF
E
The check bits, c1 through c6, contained in ESF(n + 1) will always be those associated with the contents of
ESF(n), the immediately preceding ESF. When there is no ESF immediately preceding, the check bits may be
assigned any value.
For the purpose of CRC-6 calculation only, every F bit in ESF(n) is set to 1. ESF(n) is altered in no other way.
The resulting 4632 bits of ESF(n) are used, in order of occurrence, to construct a polynomial in x such that the
first bit of ESF(n) is the coefficient of the term x
The polynomial is multiplied by the factor x
+ x + 1. The coefficients of the remainder polynomial are used, in order of occurrence, as the ordered set of
check bits, c1 through c6, that are transmitted in ESF(n + 1). The ordering is such that the coefficient of the term
x
check bit c6.
, D
5
in the remainder polynomial is check bit c1 and the coefficient of the term x
Format
L
, CRC-6) set to 1 during calculations). The CRC-6 bits transmitted in ESF will be determined as follows:
2 errored frame bits (F
2 errored F
2 errored frame bits (F
2 errored F
3 errored frame bits (F
2 errored F
sums within a one second interval if loss of frame alignment due to excessive CRC-6 errors is
enabled in FRM_PR9.
Number of Errored Framing Bits That Will Cause a Loss of Frame Alignment Condition
(continued)
T
T
E
bits out of 4 consecutive F
bits out of 4 consecutive F
bits out of 4 consecutive F
T
T
T
or F
or F
or F
6
, and the result is divided, modulo 2, by the generator polynomial x
S
S
S
) out of 4 consecutive frame bits if FRM_PR10 bit 2 = 1.
) out of 4 consecutive frame bits if FRM_PR10 bit 2 = 1.
) or channel 24 FAS pattern out of 12 consecutive frame bits.
4631
and the last bit of ESF(n) is the coefficient of the term x
T
T
E
bits if PRM_PR10 bit 2 = 0.
bits if FRM_PR10 bit 2 = 0.
bits or optionally 320 or more CRC-6 errored check-
TFRA08C13 OCTAL T1/E1 Framer
0
in the remainder polynomial is
0
.
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6