Vodavi Starplus DHS, Technical Manual

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3-4 DHS-E Description
Power Supply
The power supply circuitry of the DHS-E incorporates a linear design transformer with a
choice of input voltage taps. The transformer primary windings are shipped wired for
117V AC applications. Since the power supply is linear in design the output voltage varies
between 21.6V DC 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 DPDT (Double Pole Double
Throw) 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 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 to the BCU. When equipped, the BCU will maintain complete
system operation during commercial power outages. A current draw/configuration chart
is included in this document (refer to
Table 3-11: Battery Sizing Chart ).
Central Processor Unit (CPU)
The CPU board is standard in the Basic KSU. This board contains all circuitry required to
control the fully equipped
DHS-E . Six bus connectors are provided where the station/CO
line interface 3 x 8 Module is connected. All digital voice switching and call processing
data switching is accomplished on the CPU board. The CPU board also contains a 2400
baud modem for remote programming.
Modem
The built-in 2400 baud modem will work with DISA lines or transferred lines. It will not
operate with Direct Ringing CO lines. Set the “RMT X_RATE” to 2400 baud.
3 x 8 Module
The 3 x 8 module provides interface of three loop-start CO lines and eight DHS-E 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 & 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 MDF (Main Distribution Frame). Station
power and signaling to the digital key telephones are provided via a single twisted pair
from the 3 x 8 module.
When installing a 3 x 8 Module in location CN4, the Extender Ribbon Cable that was supplied
with the KSU must be utilized. Do not lose this cable; it is irreplacable.