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-Lawto µ255, and
A-Law to A-Law. These values are selected to meet theEIA loss and level
plan. See Table 355 "Digital pad valuesand offset allocations" (page 871).
Table355
Digital pad values and offset allocations
Offset PAD set 0 PAD set 1
00dB –7db
12dB –8db
23dB –9db
34dB –10db
45dB 0.6db
56.1dB 7db
68dB 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, Nor tel Networks
.