Nortel Networks Circuit Card 311 User Manual
Page 935
Architecture
935
The NTAK79 interfaces to one DS-30X bus which contains 32
byte-interleaved timeslots operating at 2.56 Mb. Each timeslot contains 10
bits in A10 message format; 8 are assigned to voice/data (64 Kbps), one to
signaling (8 Kbps), and one is a data valid bit (8 Kbps).
The incoming serial bit stream is converted to 8-bit parallel bytes to be
directed to padding control.
The signaling bits are extracted and inserted by the A07 signaling interface
circuitry. Following is the mapping of the DS-30X timeslot number to the
PCM-30 channel number. Timeslots 0 and 16 are currently unused for PCM.
The NTAK79 interfaces to one DS-30X bus which contains 32
byte-interleaved timeslots operating at 2.56 Mb. Each timeslot contains 10
bits in A10 message format; eight are assigned to voice/data (64 kbps), one
to signaling (8 kbps), and one is a data valid bit (8 kbps).
The incoming serial bit stream is converted to 8-bit parallel bytes to be
directed to padding control.
The signaling bits are extracted and inserted by the A07 signaling interface
circuitry. The DS-30X timeslot number is mapped to the PCM-30 channel
number. Timeslots 0 and 16 are currently unused for PCM.
Digital PAD
Software selects A-Law or Mu-Law and one of 32 possible PAD values for
each channel. These values are provided in a PROM through which the
data is routed. The idle code for A-Law is 54H and for Mu-Law is 7FH. The
unequipped code is FFH for both A-Law and Mu-Law. As the idle code
and unequipped code can be country dependent, the software instructs
the NTAK79 to use different codes for each direction. The 32 digital pads
available are listed in
Table 387 "Digital pad values and offset allocations"
. The values shown are attenuation levels; 1.0 dB is 1 dB of loss
and –1.0 dB is 1 dB of gain.
Table 387
Digital pad values and offset allocations
PAD SET 0
PAD SET 1
Offset
PAD
Offset
PAD
0
0.6 dB
0
0.0 dB
1
1.0 dB
1
–1.0 dB
2
2.0 dB
2
–2.0 dB
3
3.0 dB
3
–3.0 dB
4
4.0 dB
4
–4.0 dB
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
01.04
Standard
Release 5.0
23 May 2008
Copyright © 2003-2008, Nortel Networks
.