Vodavi Starplus DHS, Техническое руководство

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2-4 DHS General Description
Power Supply
The power supply circuitry of the DHS incorporates a linear design transformer with a
choice of input voltage taps. The transformer primary windings are shipped wired for
117V AC applications; a factory insulated tap wire may alternatively be connected for
230V AC applications. Since the power supply is linear in design the output voltage varies
between 21.6 and 32V DC depending on load and stability of the input voltage. The
output voltage is delivered to the CPU board for distribution and rectified there for logic
and control voltages.
Two fuses are equipped on the power supply board, one for AC input over-voltage
protection and one for DC output over-voltage protection. A Double Pole Double Throw
(DPDT) switch is accessible from outside of the KSU when the KSU cover is in place. The
DPDT switch will simultaneously switch AC input and DC output circuits ON and OFF.
In the event battery backup operation is desired and equipped via the optional DHS
Battery Charging Unit (BCU), the KSU switch may be used to switch OFF/ON power from
both sources.
The power supply wiring harness is equipped with a mate-n-lock connector on the DC
output for connection of the
DHS BCU. When equipped, the BCU will maintain complete
system operation during commercial power outages. A current draw/configuration chart
is included in this document for assistance in selecting the appropriate batteries for use
in the BCU. Please consult the BCU manual for installation precautions and proper battery
installation.
Central Processor Unit (CPU)
The CPU board is standard in the KSU. This board contains all circuitry required to control
the fully-equipped
DHS . Three bus connectors are provided where the station/CO line
interface 3 x 8 module and 6-Port CO Module are connected. The Option Module
connector and Standard MOH Module connector are also located on the CPU board. All
digital voice switching and call process data switching is accomplished on the CPU board.
3 x 8 Module
The 3 x 8 module provides interface of three loop-start CO lines and eight DHS key
telephones.
Each CO line circuit incorporates over-voltage protection, ring detector, loop detector,
loop/pulse-dial relay, current sink circuit, coupling/isolation transformer (impedance
600:Ohms), hybrid circuit and combo (CODEC and filter) polarity guard circuit and radio
frequency noise filter.
Each digital key telephone port is comprised of a proprietary transceiver designed using
ISDN type 2B+D architecture.
Physical connection of stations and CO lines to the 3 x 8 module is made through one
male 25-pair, amphenol-type connector to the Main Distribution Frame (MDF). Station
power and signaling to the digital key telephones are provided via a single twisted pair
from the 3 x 8 module.