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10.
DC POWER
Your controller has only a modest power requirement, which can be supplied by the repeater's own
12 V power supply in most cases.
The controller's Main Board and Telephone Interface Module together require +12 V to +15 V DC at
less than 100 mA.
Do not exceed a supply voltage of +15 V! The controller's DC power input is protected by a 15-volt
transient suppressor, which will start to draw current when the DC input voltage exceeds this limit.
The controller does not require a regulated power source, since it contains local voltage regulator
ICs for powering its analog and digital circuits. However, your power source must be free of "sags"
that may occur, for example, when the transmitter is keyed. Also, not that if significant ripple is
present on the power source output, the ripple "peaks" must not exceed +15 V, and the ripple
"valleys" must not fall below +12 V.
The controller contains circuitry to protect the data stored in memory during power outages. No
external battery backup is needed to prevent loss of memory data. However, the controller cannot
operate without external power, and owners may wish to provide backup power to both the repeater
and the controller to ensure continuous service during utility power outages.
Power can be supplied to the controller via the 2.5 mm x 5.5 mm DC power plug (supplied). The
center hole of the plug forms the positive (+) connection, and the sleeve forms the negative (-)
connection.
Instead of using the 2.5 mm connector, you may supply power to the 6K via pin 18 of connector J2.
You must shunt the 2-pin header labeled "P7" and "PWR" on the 6K Main Board.
The 2.5 mm DC power jack was retained in the 6K to allow easy upgrading of 5K installations to the
6K.
NOTE: Pin 18 of J2 is a ground pin in the 5K controller. Before shunting the P7/PWR header on
the Main Board, be sure pin 18 is not connected to ground in your 5K cable.
Here's a special note to owners of alternatively-powered repeaters (solar, fuel cell, battery, etc.):
Your controller is designed to behave predictably when the DC power input is slowly reduced! This
behavior is important to prevent damage to the power source. For example, some controllers will
suddenly stop operating (microprocessor reset) when a low voltage limit is reached. If an output,
such as the transmitter PTT line, was enabled at the time, then the transmitter could stay keyed
until the power source failed. Your S-COM controller will cease microprocessor operation when the
power supply voltage fails, but it will also force the digital outputs off at that time. This condition will
be held until the power source voltage drops considerably lower. With little load on the source, this
should take a long time to occur.
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6K V1.02 03-16-91
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