Nortel Networks Circuit Card - Manual (Page 160)

Page 160 of 906 NT1R20 Off-Premise Station Analog Line card
553-3001-211 Standard 3.00 August 2005
Functional description
This functional description of the NT1R20 Off-Premise Station (OPS) analog
line card is divided into two parts. First, a description of the card’s control,
signaling, and power interfaces is given, followed by a description of how the
card itself functions. See Figure 22.
Figure 22
OPS analog line card – block diagram
Input/output
interface
control
Codec
PCM
Micro-
controller
DS-30X
interface
5.12 MHz
clock
Tx PCM
Async card
LAN link
Front
panel
LED
Card LAN
interface
Tip
Line interface units 0–3
Ring
Codec
PCM Analog
hybrid
XFMR
Signaling relays
(ringing, battery
reversal)
Line interface units 4–7
Line interface unit power
Rx PCM
1 kHz
frame sync
Controller
card
Line
signaling
interface
Control
logic
Reg
Signaling
and status
Address/
data bus
553-6193
Power
supplies
+ 5 V dc
analog
hybrid
±15 V dc
analog
power
+8.5 V dc
+ 5 V dc logic power
Ringing
– 48 V dc
battery
Rsync
Analog
telephone
lines
Tip
Ring
Analog
telephone
lines
Loop current/
dialpulse detect
Analog
hybrid
XFMR
Signaling relays
(ringing, battery
reversal)
Loop current/
dialpulse detect
Card slot
address
Backplane