Keymile SUPM1 - Page 18

User Manual
SUPM1
page 18 of 94© KEYMILE December 2015 EN/LZTBU 372 129/1 RC
94
Functions and Specifications
Please note:
With the MCAS earth calling mode the ringing voltage is 40 V
AC
unbalanced,
applied to the b-wire only.
The ringing voltage is superimposed on both, the a-wire and the b-wire. It is a contra directional voltage. The difference
of these two voltages gives the ringing voltage.
The ringing signal has a DC offset of about 20 V
DC
.
During ringing pause the normal on-hook voltage is applied to the line.
Table 14: Signalling specification - ringing voltage (part 1) (continued)
Feature
Ringing Voltage
[V]
Time
+U
R
/2 + 10 V
Ringing
+10
0
-10
Ringing
Voltage
U
R
+ 20 V
Ringing Pause
-U
R
/2 - 10 V
b-wire
a-wire
Ri ngi ng
Voltage
U
R
– 20 V
Ringing
Ringing
Voltage
U
R
Table 15: Signalling specification - ringing voltage (part 2)
Feature Rating or standard
Ring signal form sinusoidal
Ring frequencies f
RING
16 2/3, 20; 25; 50 Hz ± 3 Hz
Maximum ring signal voltage ≤ 75 V
RMS
, unloaded
Minimum ring signal voltage ≥ 65 V
RMS
, maximum load
Maximum load per subscriber
@ f
RING
≤ 25Hz
or @ f
RING
= 50 Hz
or
3 REN
1.6 REN
2.5 kΩ
Definition of 1 REN: 1.8 kΩ + 850 nF
= 7.7 kΩ -76.5° @ 25Hz
Maximum load per SUPM1 unit for simultaneous ringing 24 REN
Maximum ringing current (short circuit): ≤ 120 mA
Ringing signal crest factor ≥ 1.2
Ringing delay CAS → a/b-wire ≤ 40 ms
Ringing distortion CAS → a/b-wire ≤ 40 ms
Ringing cadence according to CAS
Table 16: Signalling specification - metering
Feature Rating or standard
Each subscriber circuit on the SUPM1 unit has its own metering generator. Metering pulses can be sent to the line dur-
ing off-hook and up to 25.5 seconds after going on-hook.