PBL 386 20/2
14
DR
Input to the ring trip comparator. With DR more positive than DT the detector output, DET, is at logic
level low, indicating off-hook condition. The external ring trip network connects to this input.
15
16
17
C3
C2
C1
C1, C2 and C3 are digital inputs (internal pull-up) controlling the SLIC operating states.
Refer to section "Operating states" for details.
18
DET
Detector output. Active low when indicating loop detection and ring trip, active high when indicating ground
key detection.
19
20
21
NC
No internal Connection.
VCC
PLD
+5 V power supply.
Programmable Loop Detector threshold. The loop detection threshold is programmed by a resistor
connected from this pin to AGND.
22
23
POV
PLC
Programmable Overhead Voltage. If pin is left open: The overhead voltage is internally set to min 1.0 V in
Off-and On-hook. If a resistor is connected between this pin and AGND: the overhead voltage can be set to
higher values.
Prog. Line Current, the constant current part of the DC feed characteristic is programmed by a resistor
connected from this pin to AGND.
24
25
26
REF
NC
A Reference, 49.9 kΩ, resistor should be connected from this pin to AGND.
No internal Connection.
RSN
Receive Summing Node. 200 times the AC-current flowing into this pin equals the metallic (transversal) AC-
current flowing from RINGX to TIPX. Programming networks for two-wire impedance and
receive gain connect to the receive summing node. A resistor should be connected from this pin to AGND.
27
28
AGND
VTX
Analog Ground, should be tied together with BGND.
Transmit vf output. The AC voltage difference between TIPX and RINGX, the AC metallic voltage, is
reproduced as an unbalanced GND referenced signal at VTX with a gain of one (or one half, see pin PTG).
The two-wire impedance programming network connects between VTX and RSN.
SLIC Operating States
State
C3
C2
C1
SLIC operating state
Active detector
0
1
2
3
4
5
6
7
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
Open circuit
Ringing state
Active state
Not applicable
Not applicable
Active state
-
Ring trip detector (active low)
Loop detector (active low)
-
-
Ground key detector (active high)
-
-
Not applicable
Not applicable
Table 1. SLIC operating states.
9
ERICSSON [ ERICSSON ]
