How the Unit Works
© Diebold Election Systems, Inc. 2002 AccuVote-OS Hardware Guide
10
The memory card interface accepts 32Kb and optionally 64Kb and 128Kb credit-card sized
EPSON memory cards. A memory card has forty terminals covered by a spring-loaded shutter
which is automatically pushed back upon insertion into the memory card interface. These
terminals fit into the interface’s forty-pin socket. Since the memory card is connected to a live
system, protection resistors have been added in series with the socket in order to prevent
possible damage from a short circuit on one of the pins, causing an operational failure on the
CPU.
The average life of the battery in the 32Kb RAM card is about 10 years. The average battery life
for the 64Kb RAM card is approximately 8.5 years. The average battery life for the 128Kb RAM
card is about 5.7 years.
2.1.11.
LCD module interface
The AccuVote-OS features a two by sixteen character LCD (Liquid Crystal Display) unit with an
intelligent on-board controller. It is used to display messages and prompts in which each of a
memory’s card’s election modes as well a diagnostic and setup information. LCD prompts are
synchronized with responses provided on the Acc-Vote and buttons, which are mounted directly
on the CPU board and protrude out the front of the enclosure below the LCD.
The LCD is connected by a fourteen-conductor ribbon cable to the CPU board’s P14.
2.1.12. Printer
interface
Each AccuVote-OS contains a light-weight, seven wire dot matrix M-180 Series EPSON printer
controlled directly by the CPU, which prints twenty-four columns on 2¼” wide paper. Both the ink
cartridge and paper roll are easily replaceable using procedures described in the section titled
Pre-Election maintenance
in
Chapter 23: Maintenance
in the
AccuVote-OS Precinct Count
User’s Guide
.
The printer is mounted above the CPU board on a small metal bracket and is connected P15 on
the board via a fifteen-conductor flat ribbon cable. All timing and dot matrix information is
controlled by the CPU's program. The printer motor is powered by a 5-volt DC regulator which is
switched on and off by the CPU via a TIP32 transistor. Parallel drivers provide dynamic braking
of the motor whenever the motor power is turned off.
Data to be printed is output via CPU I/O port 0 in the active low state. A strobed hex inverter is
used to pulse the data to the 5 volt printer solenoids which require 3 amps of current when
energized. The solenoids are powered from the 14 volt DC supply, which is set up to emulate the
energy usage required by the solenoids.
2.1.13. RS-232
serial interface
A full duplex serial channel, configured as Data Terminal Equipment (DTE), is provided for
communication with a host computer. The interface requires a flat ribbon cable from the CPU
board’s P10 to a DB9-M (male) connector, which constitutes the main serial port at the rear of the
enclosure. An RS232C cable with a nine pin female connector is used to connect the main serial
port to the host computer.
2.1.14. Ballot
deflector
A device for deflecting write-in or blank ballots into the alternate compartment in the ballot box is
driven directly from connector P3 on the CPU board.
The deflector motor is driven with 14 volts DC power. Two FET transistors control the motor.
One transistor controls the relay that switches the direction that the deflector moves while the
other transistor toggles the motor power on and off.
