Nortel Networks Circuit Card 311 User Manual
Page 871
Architecture
871
•
Receive voice: inserts digital pads and provides graceful entry into
T-Link data mode when the data module connected to the DTI/PRI trunk
is originating the call.
•
T-Link data: a set of transmit and receive vectored subroutines which
provides T-Link protocol conversion to/from the DM-DM protocol.
•
Receive ABCD filtering: filters and debounces the receive ABCD bits
and provides change of state information to the system.
•
Diagnostics
•
Self-test
Digital pad
The digital pad is an EPROM whose address-input to data-output transfer
function meets the characteristics of a digital attenuator. The digital
pad accommodates both µ255-law and A-Law coding. There are 32
combinations each for µ255 to µ255, µ255 to A-Law, A-Law to µ255, and
A-Law to A-Law. These values are selected to meet the EIA loss and level
plan. See
Table 355 "Digital pad values and offset allocations" (page 871)
Table 355
Digital pad values and offset allocations
Offset
PAD set 0
PAD set 1
0
0dB
–7db
1
2dB
–8db
2
3dB
–9db
3
4dB
–10db
4
5dB
0.6db
5
6.1dB
7db
6
8dB
9db
7
–1dB
10db
8
–3dB
11db
9
–4dB
12db
A
idle code, 7F
3db
B
unassigned code, FF
14db
C
1dB
spare
D
–2dB
spare
E
–5db
spare
F
–6db
spare
Nortel Communication Server 1000
Circuit Card Reference
NN43001-311
01.04
Standard
Release 5.0
23 May 2008
Copyright © 2003-2008, Nortel Networks
.