lucl9311gp-dt ETC-unknow, lucl9311gp-dt Datasheet - Page 32

• Manufacturer Part Number: lucl9311gp-dt
• Description: Line Interface Line Access Circuit Full-feature Slic With High Longitudinal Balance, Ringing Relay,and Gr-909 Test Access
• Manufacturer: ETC-unknow

Ringing Relay, and GR-909 Test Access
Applications
dc Characteristics
Battery Feed
The L9311 operates in a dc unbalanced mode. In the
forward active state, under open circuit (on-hook) con-
ditions, with the default overhead chosen, the tip to ring
voltage will be a nominal 5.5 V less than the battery.
This is the overhead voltage. The tip and ring overhead
is achieved by biasing ring a nominal 3.5 V above bat-
tery and by biasing tip a nominal 2.0 V below ground.
During off-hook conditions, some dc resistance will be
applied to the subscriber loop as a function of the phys-
ical loop length, protection, and telephone handset. As
the dc resistance decreases from infinity (on-hook) to
some finite value (off-hook), the tip to ring voltage will
decrease as shown in Figure 13.
As illustrated in Figure 13, as loop length decreases,
the tip to ground voltage will decrease with a slope cor-
responding to one-half the internal dc feed resistance
of the SLIC (typical 75
will also decrease with a slope corresponding to one-
half the internal dc feed resistance of the SLIC, until the
SLIC reaches the current-limit region of operation. At
that point, the slope of the ring to ground voltage will
increase to the sum of one half the internal dc feed
resistance plus approximately 10 k .
32
VRING TO GND
VTIP TO GND
V
BAT
Figure 13. Tip/Ring Voltage
(1/2)R
(1/2)R
(continued)
BEGIN CURRENT LIMITING
dc
dc
(continued)
). The ring to ground voltage
DECREASING LOOP LENGTH
(1/2)R
12-3431a (F)
dc
+ R
LIM
The dc feed characteristic can be described by:
I
V
where:
I
V
V
R
resistance.
R
R
Notes:
V
V
I
LOOP
LOOP
LIM
BAT1
BAT2
V
T/R
T/R
OH
LOOP
P
dc
Figure 14. L9311 Loop Current vs. Loop Voltage
BAT
= protection resistance.
= 40 mA (R
= SLIC internal dc feed resistance.
= overhead voltage.
=
= dc loop voltage.
= –48 V.
= –24 V.
50
40
30
20
10
=
= dc loop current.
0
= loop resistance, including wire and handset
--------------------------------------------------------------- -
0
------------------------------------------------------
R
= battery voltage magnitude.
V
R
LOOP
BAT
LOOP
V
5
PROG
BAT
–
+
+
V
2R
10
= 66.5 k ).
–
OH
2R
V
P
OH
P
+
15
+
LOOP VOLTAGE (V)
R
R
R
LOOP
dc
dc
20
10 k
1
25
Agere Systems Inc.
30
35
July 2001
40
12-3050.g (F)
R
1
dc
45