5
January 24, 2005
SECTION 2: DC Functionality and AC Performance Testing
DC Power-up Testing
After correct initial power-up, the DC tests measurements
shown in table 4 should be performed to verify proper
operation prior to performing the tests that follow.
Uncommitted Switch DC Test
When the jumpers JP1 and JP2 are installed, the
uncommitted switch is connected across Tip and Ring. The
test load of diode D
TA
and resistor R
TA
(100
Ω)
will connect
across the Tip and Ring terminals when the uncommitted
switch is turned on. The DC load will cause a DC loop
current flow at the loop current limit value of 25mA, resulting
in a switch hook detect indication by the DET LED. The DC
test load is a convenient method of checking the DC
operation of the RSLIC, however, operating the test load with
BSEL at Vbh (BSEL = 1) can cause excessive heating of the
RSLIC, causing thermal shutdown as indicated by the ALM
LED.
RSLIC Ringing Tests
Description
The ringing configuration supports full evaluation of the
ringing capability of the ISL5585 and HC55185 devices. The
evaluation board design does not include a ring signal
generator. Ring signals can be provided with an external
generator through the VRS BNC connector, or can be
sourced through the CODEC by inserting jumper JP5 -
CODEC.
Operation of the RSLIC in the ringing mode results in
dangerous voltages appearing at the tip and ring terminals.
Extra care is required when connecting external equipment
to the tip and ring terminals during testing to prevent
personnel injury and equipment damage.
Jumper Settings
The jumper JP5 provides three positions for different ringing
techniques.
CODEC Ringing
Most test equipment designed to evaluate the CODEC PCM
interface are capable of output frequencies as low as 20Hz.
If such a piece of equipment is available, then CODEC
ringing can be evaluated. The digital interface to the CODEC
is provided by the BNC connectors J10 thru J13. Verify JP11
TABLE 4. EVALUATION BD. DC TEST VOLTAGES
Tip and Ring Voltages (Volts) - Tip to Ring Open Circuit; Vbl = -28V; Vbh = -100V
DC Values (±20%)
OPERATING MODE
F2, F1, F0
E0
SWC
BSEL
TIP TO GND
RING TO GND.
Low Power Standby
0, 0, 0
x
1
1
-0.6V
-49V
Forward Active
0, 0, 1
x
1
0
-4.0V
-19.4V
Unbalanced Ringing
0, 1, 0
n/a
n/a
n/a
-0.6V
-50V
Reverse Active
0, 1, 1
x
1
0
-19.4V
-4.0V
Ringing
1, 0, 0
x
1
1
-50V
-50V
Forward Loop Back
1, 0, 1
x
1
0
-4.4V
-19V
Tip Open
1, 1, 0
x
1
1
Float
-49V
Power Denial
1, 1, 1
x
1
x
Float
Float
Uncommitted Switch (DET LED on)
0, 0, 1
1
0
0
-12.4V
-15.2V
FIGURE 2. TEST LOAD SWITCHING
RING
TIP
R
TA
D
TA
SW+
SW-
SWC
JP1
JP2
TABLE 5. JP5 JUMPER POSITIONS
JP5 POSN
DESCRIPTION
CODEC
Connects the CODEC receive output to the device
ringing input. Signal path is AC coupled.
EXT
Connects the VRS connector J9 to the device ringing
input. Signal path is AC coupled.
TRAP
Connects the VRS connector J9 thru RC network to
the device ringing input. Signal path is AC coupled.
Application Note 1168
