Nortel NT1R20 Description page 226

Page 202 of 290
Figure 57
Digital line card—block diagram
DS-30X loop
Tx PCM
Rx PCM
5.12 MHz clock
1 kHz frame sync
Front
panel
LED
Card slot
address
Card
LAN link
Power
supplies
553-3001-105 Standard 5.00 June 1999
NT8D02 Digital Line Card
+10 V dc
Digital
line
interface
Address/
data bus
+10 V dc
Digital
line
interface
Micro-
controller
Sanity
timer
Card LAN
interface
Line interface units 0–7
Line interface units 8–15
±15 V dc
+15 +10
Reg
TCM
Tip
loop
Ring
interface
circuit
TCM
Tip
loop
Ring
interface
circuit
+ 5 V dc
553-6163
Digital
phone lines
Digital
phone lines