Keymile SUPM1 - Power Management; Figure 18: Power Management for Normal Priority Subscribers

User Manual
SUPM1
page 59 of 94© KEYMILE December 2015 EN/LZTBU 372 129/1 RC
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Functional Description
5.13 Power Management
The subscriber telephone sets in the PSTN (POTS) application are powered
by the access node, i.e. by the SUPM1 unit. The SUPM1 unit is designed to
be able to deliver the power to all 16 subscribers simultaneously. If the
simultaneous ringing of several connected telephone sets it is possible that
the requested total loop current exceeds the capability of the onboard power
supply. To prevent an uncontrolled behaviour of the loop powering, SUPM1
has a built-in power management feature avoiding the overload of the loop
current power supply.
Depending on the power state the setup of new calls is only allowed with a
reduced current, or not allowed at all. There are three power states on
SUPM1:
•In the normal state the unit provides the configured loop current without
restrictions.
• If the total loop current rises above the threshold 1 the power state 1 is
reached. In this state any new calls of normal priority subscribers are set
up with a reduced loop current. New calls of high priority subscribers and
ongoing calls are not affected.
• If the total loop current rises above the threshold 2 the power state 2 is
reached. The loop current of all ongoing calls of normal priority subscrib-
ers are modified to the reduced loop current.
In the power state 2 no additional calls of normal priority subscribers are
possible.
High priority subscribers are not affected.
A reduced loop current state of a subscriber port persists until the call is ter-
minated.
Figure 18: Power management for normal priority subscribers
The power management feature and the value of the reduced loop current
are configurable in the AP: /unit-x, Configuration - Advanced Unit Parame-
ters.
Please note:
In the V5CAS and MCAS direct line operation modes up to three high priority
ports can be configured per SUPM1 unit.
In the other operation modes all ports are handled as normal priority ports.
Total loop current
[mA]
Time
normal
state
power
state 1
power
state 1
power
state 2
normal
state
Threshold 2
Threshold 1
new calls are setup
with their normal
loop current
new calls are setup
with the reduced
loop current
all calls are modified
to the reduced loop
current
no new calls
are allowed
new calls are setup
with their normal
loop current
power
state 1
power
state 2
new call s ar e setup
wi th the r educed
loop current