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Preliminary Data Sheet, Rev. 1
October 2000
TMXF28155 Super Mapper
155/51 Mbits/s SONET/SDH x28/x21 DS1/E1
339
Lucent Technologies Inc.
M13/M23 Mux/Demux Block Functional Description
(continued)
B3ZS Encoder (GR-499)
The transmit DS3 device output can either be in the form of unipolar data (M13_DS3POS_DATA when
M13_BIPOLAR = 0 (Table 261)) or positive data, and negative data (M13_DS3POS_DATA, and M13_DS3NEG
when M13_BIPOLAR = 1). If M13_BIPOLAR = 1, the DS3 data is B3ZS encoded with M13_DS3POS_DATA = 1
indicating a positive pulse and M13_DS3NEG = 1 indicating a negative pulse.
The B3ZS encoder block accepts data output from the M23 multiplexer and when M13_BIPOLAR = 1, performs
coding as follows. For each input data bit that is a 1, the encoder outputs a 1 (or pulse) on either its positive or neg-
ative output. The positive or negative output is chosen such that the resulting pulse is opposite in polarity to the last
non-zero output.
For each input data bit that is a 0, the encoder outputs zeros on both its positive and negative outputs, unless doing
so would cause 3 consecutive output periods of positive and negative zeros. In the latter case, the 3 consecutive
input zeros are output as either [00V] or [B0V], where B is a pulse on either the positive or negative output that is
opposite in polarity to the last non-zero output, and V is a pulse that is the same polarity as the last non-zero out-
put. The choice of [00V] or [B0V] is made so that the polarity of consecutive V-pulses alternates (which is equiva-
lent to forcing the number of B-pulses between successive V-pulses to be odd).
When M13_BIPOLAR = 1, the user can force errors in the bipolar coding by setting M13_BIPOL_ERR (Table 259)
to 1. When this is done, the M13 transmits the next 1 as a bipolar violation.
DS3 R-to-T Loopback
The received DS3 signal can be looped directly back to the transmit DS3 output. If either M13_LOOP_R_TO_T = 1
(Table 261), or both M13_AUTO_FLB = 1 (Table 260) and M13_DS3_FLB_DET = 1 (Table 252) (see FEAC on
page 336), the loopback is activated. (During loopback, the SMPR_RDS3POS_DATA and SMPR_RDS3NEG_BPV
input signals are looped to the M13_DS3POS_DATA and M13_DS3NEG outputs respectively.)
DS3 Transmit Path Interface
When cross connected to the DS3 device pins, the DS3 data out DS3POSDATAOUT (Pin R22) and
DS3NEGDATAOUT (Pin P22) is clocked out on the falling edge of DS3DATAOUTCLK (Pin N22)
If the M13 DS3 interface is optioned for loop timing (M13_LOOP_TIME = 1), the DS3 data is clocked out on the ris-
ing edge of DS3DATAINCLK (Pin J22).