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EPM-4 Reference Manual Reference – 25
POWER REQUIREMENTS
The EPM-4 only requires +5 volts (±5%) for proper operation. The voltage required for the RS-
232 ports is generated with an on-board DC/DC converter. A variable low-voltage supply circuit
provides power to the CPU and other on-board devices.
The exact power requirement of the EPM-4 depends on several factors peripheral connections,
type and number of expansion modules, and attached devices. For example, AT keyboards
typically draw their power directly from the
EPM-4, and driving long RS-232 lines at high speed
can increase power demand. Reducing the CPU speed from 133 MHz to 100 MHz via the BIOS
settings will save approximately 0.5 W.
L
ITHIUM BATTERY
Warning! To prevent shorting, premature failure, or damage to the lithium battery, do not
place the unit on a conductive surface such as metal, black conductive foam, or the
outside surface of a metalized ESD protective pouch. The lithium battery may
explode if mistreated. Do not recharge, disassemble, or dispose of in fire. Dispose
of used batteries promptly.
Batteries of different voltages are used on different revisions of the EPM-4, as shown below:
EPM-4 Revision
Battery Type
Min. Operating
Voltage
Reorder Part No.
Rev 4 and above 3.0V 2.5V T-HB3/5-2
Rev 2 3.5V 3.0V T-HB3/5-3
If the operating voltage drops below the minimum, contact the factory for a replacement. Life
expectancy under normal use is approximately 10 years.