Atlas O Scale 21st Century Signal User manual

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21st
st Centur
Century Signal System y Signal System™
™
2-Rail Manual
2-Rail Manual
Scale Track System
Scale Track System

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TABLE OF CONTENTS
Introduction..................................................................................................................2-3
Road Signal Board Diagram and Definitions ..................................................................4-6
Tips for Handling the Circuit Board ..................................................................................6
2-Rail Detector Board Diagram and Definitions ................................................................7
The Basic Installation of One Signal ..............................................................................7-9
How to Make an Insulated Rail Section ..........................................................................10
Installing the 2nd Signal: Adding the Multiple Integration Feature................................11-12
Approach Mode and Bi-Directional Signaling with Examples ......................................13-15
Setting the Jumper Plugs ................................................................................................16
How to Use the DOUT Feature........................................................................................17
Atlas O Signal System Product Listing ............................................................................18
Contact Information ......................................................................................................18
Warranty ........................................................................................................Back Cover

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INTRODUCTION
Dear "O" Enthusiast,
Prototype signal systems are one of the most familiar trackside details to be incorpo-
rated on miniature rail systems. Ever since the modern position light signals were intro-
duced by the railroads in the mid-1920's, model train manufacturers have been eager
to offer them as the quintessential layout accessory. While capturing the appearance
of the real thing, operation, in most cases, has been far less than prototypical...until
now.
The Atlas O 21st Century Signal™System represents a quantum leap in model signal
operation and design. By following the simple installation instructions, the realistic sig-
nal structures will provide you with prototypical operation that can be tailored to any
layout. The signal circuit board is the "heart" of the system. Installed in the detailed
trackside relay shed (or mounted under your layout), the circuit board is capable of
four modes of signal operation:
• Stand-Alone Signal Operation - Each signal is completely independent and
gives a timed Red-Yellow-Green aspect operation. (Simplest hook-up)
• Integrated Operation - Each signal is connected together and the Red-Yellow
Green aspects are controlled by the blocks and signals in front of and behind your
train. Hook-up between signals is accomplished easily with the Atlas O Signal Cable
(Items #6937-6939), pre-packaged in lengths of 7', 15' and 25'.

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• Approach-Only Signal Operation - On some prototype railroads, signals
are off until a train approaches. The Atlas O Signal system has the provisions to
duplicate this operation.
• Complex Signaling (in conjunction with the signals and signal boards offered
by Custom Signals, Inc.) - The Atlas O Signal System has been designed to be fully
compatible with the products offered by Custom Signals, Inc., one of the hobby's
premier custom signal builders.
As you can see by the features included with Atlas O's 21st Century Signal System,
expert knowledge of the prototype was essential. Many hours and intense research
were put into the design of the system to achieve prototype operation in a user-friend-
ly manner. As a result, I would like to thank the following individuals who have assist-
ed with this project from concept to realization: Gary Emmich, Steve Horvath and Terry
Christopher.
Happy Railroading!
Sincerely,
Jim Weaver,
Vice President, Atlas O, LLC

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SIGNAL CONTROL BOARD
The signal control board is the "electronic
brain" behind the operation of the signal
system. By taking a few minutes to study
the diagram and read the definitions, you
can familiarize yourself with the overall
operation of the signal system.
DEFINITIONS
1. J1- (Jack 1) - J1 is used for multiple inte-
grated installations only. In integrated installa-
tions, J1 is plugged into J2 of the following
board. Atlas O carries a variety of modular con-
nectors in 7',15', and 25' lengths, (Item #'s
6937-6939). See page 11 for further explana-
tion of integrated installation.
2. J2- (Jack 2) - See J1 above.
3. J3- (Jack 3) - J3 is the connection for the 8
pin modular jack from the signal itself.
4. J4- (Jack 4) - J4 is a screw-type power
connection terminal strip. It allows stand-alone
or daisy-chaining of power leads.
SIGNAL CONTROL
BOARD

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a. COM - COM is the common, or ground. In stand-alone installation, it is connected to the
power supply. Power is 6-22 volts AC or DC. While the signal system will run on AC,
Atlas O recommends DC for expansion. Use black wire.*
b. PWR - PWR is the positive or (hot) AC or DC power. In stand-alone installation, it is connected
to the power supply. Use red wire.
c. COM - The second COM connection is used in multiple integrated installations. This COM is
connected to the next signal board. Use black wire.
d. PWR - The second PWR connection is also used in multiple integrated installations. This PWR
is also connected to the next signal board. Use red wire.
5. J5- (Jack 5) - J5 is a screw-type connection strip used for input/output connections.
a. TM - TM is the turnout module connection. It can be connected to either the Atlas O switch
signal control board for correct output to block signal control board #6930, or to Custom Signals
turnout signal control board. Use blue wire.
b. DOUT - DOUT is the optional detector output. It is used to connect an auxiliary piece of
equipment, (no more than +5VDC), such as an LED or relay. Wire color optional.
c. DIN - DIN is the detector input. It is connected to the insulated rail detector lead, (or the
detector lead from the Atlas O 2-rail detector board, (#7935 in 2-rail installations). Use green wire.
d. YIN - YIN is the yellow input. This connection is used if a second insulated block is planned to
control the yellow "aspect" of the signal independent of the "timed" yellow, which is the default
setting. Use yellow wire.

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6. J6AIN- (Jumper 6) - J6AIN is the approach input. It is a solder pad that is used with the "approach”
lighting feature.
7. JP1- (Jumper 1) - JP1 is used for “approach” lighting options. Both JP1 and JP2 come from the facto-
ry with the jumper plugs covered by a black plastic cap.
8. JP2- (Jumper 2) - JP2 is used for searchlight style signals that use a single bi-color LED for three color
output, available from Custom Signals.
9. LED1 - LED 1 is used to indicate whether the correct power is going to the circuit board. If lit, it is correct.
*(Please note-Atlas O recommends their readily available brand of 20 gauge, multi-stranded copper wire that comes in a variety
of colors, Item#'s 315-#319.
TIPS FOR HANDLING THE SIGNAL SYSTEM CIRCUIT BOARD
When handling the signal system circuit board, it is important to follow these simple guidelines to prevent any damage to the cir-
cuit board.
1. Unplug your power source before attempting to handle the signal circuit board.
2. Touch some type of metal surface. This action helps protect the circuit board from any damage that could be caused by
electrostatic discharge.
3. To avoid generating static electricity, do not walk around the room until you have completed handling or mounting the circuit
board.
4. Hold the board by its corners, taking care not to touch the components on the circuit board.
5. Turn off your power supply after every operating session.

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DEFINITIONS
TS1
PWR IN - Power from transformer or power supply
TO TRACK - Wire to insulated rail used in “Block”
LED 1 - Used for visual indication of “Block” occupancy. Will be
lit whenever “Block” is occupied
TS2
PWR - Circuit board power 6-22VAC or DC
DET - Detector output connects to “DIN” of Signal Control Board
COM - Common or return from power supply
SPARE - Unused
#7935
2-RAIL DETECTOR BOARD
THE BASIC INSTALLATION OF ONE SIGNAL
Now that you have familiarized yourself with the signal board and detector diagrams and def-
initions on pages 4-7, you are ready to install your first signal using the diagram found below.
The initial step is to determine the signal location. The signal is normally placed at the entrance
to a block. (A block is any section of track that is electrically isolated from the rest of the lay-
out.) Next to a straight track, the signal should be positioned approximately 2-3 inches from
the outside track edge. Placing a signal on a radius should be carefully done in consideration
of your longest rolling stock. Experiment with a variety of cars to determine the correct space
from the outside track edge.

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POWER SUPPLY
TO TRACK
BASIC
INSTALLATION
DIAGRAM
The signal board will be located either within the silver shed that comes with both the single and
four pack kits, (Item #’s 7930 and #7934) or it may be mounted under the table with the sup-
plied bracket. The shed can be located on either side of the track in relation to the signal. They
should, however, be in close proximity to one another as determined by the length of the signal
wire. (See diagrams on right for detailed shed and under the table positioning and installation.)

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Drill a 5/8” hole under the middle
of relay shed location. Run the red
and black power wires from the J4
terminal strip, (PWR) of the signal
board to power leads of the
unplugged source of power, (6-
22VAC or DC power pack).
Create an insulated rail section of
track. (See page 10 for detailed
instructions.) Connect the wire
from the DET terminal of the detec-
tor board to the J5 terminal strip
marked DIN on the signal board.
Drill a 1/2” hole under the signal
location and drop the plug from
your signal into the hole and work
it up through the relay shed hole.
Plug the 8 pin signal jack into the
input marked J3 on the signal
board. The installation is now
complete.
Please Note: The detector board can be attached to the underside of the layout table using double-sided foam tape.