Digital pad – Nortel Networks 1000 User Manual
Page 877
Architecture
877
NTBK50 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. Timeslots 0 and 16 are currently
unused for PCM.
Digital PAD
The software selects A-Law or µ-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 µ-Law is 7FH.
The unequipped code is FFH for both A-Law and µ-Law.
As the idle code and unequipped code can be country dependent, the
software instructs the NTBK50 to use different codes for each direction.
The 32 digital pads available are illustrated in
- values and offset allocations" (page 877)
. The values shown are
attenuation levels (1.0dB is 1 dB of loss and –1.0 dB is 1 dB of gain.
Table 370
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
5
5.0 dB
5
-5.0 dB
6
6.1 dB
6
-6.0 dB
7
7.0 dB
7
-7.0 dB
8
8.0 dB
8
-8.0 dB
9
9.0 dB
9
-9.0 dB
10
10.0 dB
10
-10.0 dB
11
11.0 dB
11
spare
12
12.0 dB
12
spare
13
13.0 dB
13
spare
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
02.06
Standard
27 August 2008
Copyright © 2003-2008 Nortel Networks
.