Astera ARC2 User manual

USER MANUAL
Radio Frequency
Remote Controller
(ARC2)
Manual Version: 3.2.2
Release Date: July. 23rd.2 1
Astera LED Technology GmbH
Address : Nahestrasse 6 -70, 55593 Rüdesheim an der Nahe, Germany Tel.: [phone] Email: [email protected]

Table of Contents Chapter 1
1 Table of Contents
1 Table of Contents..............................................................................................................................2
2 Safety..................................................................................................................................................3
3 Getting Started...................................................................................................................................4
3.1 Overview......................................................................................................................................4
3.2 LCD Display.................................................................................................................................4
3.3 Introduction..................................................................................................................................
3.4 Navigation....................................................................................................................................
3. Power Button...............................................................................................................................
3.6 Micro SD card..............................................................................................................................6
3.7 Batteries.......................................................................................................................................6
4 Preset Programs (MEMOR 1-4)......................................................................................................7
4.1 Tap-sync......................................................................................................................................7
5 Editor..................................................................................................................................................8
.1 Using the Editor...........................................................................................................................8
.2 Colors..........................................................................................................................................8
.3 Programs of the Editor.................................................................................................................8
.4 Adjustments.................................................................................................................................9
. Advanced Adjustments................................................................................................................9
6 Targeting Lamps..............................................................................................................................11
7 Setup.................................................................................................................................................12
8 Technical Data.................................................................................................................................15
9 Troubleshooting..............................................................................................................................16
10 Appendix.........................................................................................................................................17
10.1 Color Index..............................................................................................................................17
10.2 Customizable Programs...........................................................................................................18
10.3 Color Chaser for Random Modes............................................................................................19
10.4 DMX table for Effect Mode.......................................................................................................20
10. Firmware Updating Process ....................................................................................................21
11 Disposal..........................................................................................................................................23
2

2 Safety
Before you operate the unit, read this manual carefully.
Make sure to keep the manual, in case you need to consult
this manual again or you give the unit to another person.
Always make sure to include this manual if you hand out the
unit to another person.
Do not operate the unit in areas where the usage of radio fre-
quency or mobile phones is prohibited, like for example in
airplanes, or when it may cause interference or danger.
Only qualified personnel may repair this product.
Don't open the case.
This device conforms to CE -or- FCC regulations, see type la-
bel!
It radiates in the 868 MHz or 915 Mhz bands. (See “Error:
Reference source not found“, page Error: Reference source
not found for details.
Always make sure, that your national regulations allow the
use of this device!
Only insert Alkaline batteries, rechargeable batteries do not
have enough voltage to power the ARC2 remote control.
Keep batteries away from children. In case of a choking haz-
ard go to the doctor immediately.
Make sure contacts are clean before you insert batteries.
Watch the polarity.
Don't try to recharge batteries.
MAKE SURE TO FULLY CHARGE ALL BATTERY-POWERED AS-
TERA LAMPS WHEN STORING THEM.
PARTIALLY CHARGED BATTERIES WILL LOOSE CAPACITY
3

Getting Started Chapter 3
3 Getting Started
3.1 Overview
3.2 LCD Display
Definition of symbols:
(1) - Receiving
(3) - Transmitting
(4) - Inside Editor mode
(5) - Synchronization between units is active
( ) - Battery status
4
Antenna
Switch LEDs on/off
Adjust speed
Display user colors
Adjust fade time
back one level
in top level: adjust bpm
Navigate through menu,
adjust values
Choose program
Choose user colors
LCD Display
Choose groups
Update all devices in se-
lected groups with cur-
rent settings.
Home button: return to top level
Adjust brightness
Save/send value
Launch MEMORY
programs 1- ,

3.3 I ntroduction
Astera ARC2 radio frequency remote control is being used to control Astera's wireless lamps,
wireless controllers and wireless DMX transmitters. The system offers several sets of pre-
defined programs that can be quickly launched.
For advanced applications the programs can be customized over the Editor (see Chapter 5).
The replaying colors can be defined to fit a theme or corporate identity. These colors can be
used in programs which can be adjusted on speed, brightness and fading effects.
It is also possible, to address, group and synchronize several units and to stretch programs
over several lamps. For example the RAINBOW effect can be stretched over two or more
units displaying the full rainbow spectrum at the same time.
3.4 Navigation
Navigation through the system is done with the top 4 buttons
of the remote control. Enter confirms a value, + and – button
choose a value and Back moves up 1 level in the navigation.
The top level of the navigation contains the 3 sets of pre-defined memory programs
(MEMORY 1 – MEMORY 3) as well as an area to store own programs (MEMORY 4) and the
SETUP. The + and – buttons are used to navigate between them and Enter offers deeper
editing of the MEMORY programs and the setup.
From any point in the navigation, the home button can be pressed to return to the
top level of the navigation. This is especially useful when an inexperienced user
gets lost in advanced settings and is afraid he will alter important settings.
3.5 Power Button
Power Mode: LIGHT ON: Returns from BLACKOUT to normal operation.
Power Mode: BLACKOUT: Switches all targeted lamps off and keeps them in
standby, power is reduced.

Getting Started Chapter 3
3.6 Micro SD card
For special functions like saving programs and firmware update a micro SD card can be in-
serted into the ARC2.
3.7 Batteries
In many countries, the ARC2 ships without batteries due to safety regulations. If this is the
case for you, please buy 2 Alkaline AA batteries and insert them in the correct positioning
with + and – positioned correctly.
When closing the battery compartment push each corner until the compartment cover sits in
the right position. Then close the slider to fix the battery compartment closed.
6

Preset Programs (MEMORY 1-4) Chapter 4
4 Preset Programs (MEMORY 1-4)
For quickly changing the mood of a lamp or setup of lamps, the 24 pre-programed MEMORY
programs can be quickly launched and optionally be customized (see Chapter 5).
To start a MEMORY program, click one of the white buttons while in one of the 3
pre-programed MEMORY tabs on the top level of the ARC2's navigation.
If you not sure in which level you are, press the home button to reach the top level.
In addition to the 3 pre-programmed tabs (MEMORY 1-3) the MEMORY 4 tab provides room
for own creations that can be launched with the white buttons when inside this set.
MEMORY 1 decorative: This set is suited for basic events, presentations, background
lighting and a a general decorative mood. Also, this is the set
where the home-button leads to.
MEMORY 2 party slow: This set has pre-programed color transitions for dinner parties,
early hours of disco-nights etc.
MEMORY 3 party heavy: This set has fast and strong color effects, strobe-effects and
rapid changes between colors. It is suited for dancing events
and to hightlight special parts of a show.
MEMORY 4 user define: This set is not pre-programed by Astera. Chapter 5 will discuss
how its keys can be programmed with customized colors and
effects. It can be used by event-preparing companies to
prepare special programs for their customers or for quickly l
aunching them during their events.
4.1 Tap-sync
Tap-sync can be used to adjust the speed of the transitions of MEMORY 1-3 pro-
grams and programs defined by the user. It can be used to synchronize the
lamps' speed to music that is played but also to the mood of an event.
To tap-sync, while in the top level of the navigation press the tap-sync button twice
in the rhythm you want to synchronize the lamps. If you not sure in which level you
are, press the home button, then press tab-sync twice.
Tap-sync does not affect all types of programs. Only if they use a random color
chaser, tap-sync has an effect.
7

Editor Chapter 5
5 Editor
5.1 Using the Editor
The Editor is an advanced function that lets you customize the 3 sets of preset MEMORY
programs (decorative, party slow, party heavy). In addition you can save your own
programs onto MEMORY 4 user define if you want to keep the original programs in MEMORY
1-3.
To enter the editor, while in the top level of the navigation in any of the 4 MEMORY
sets, press and hold one of the white button for 2 seconds. Alternatively, when in
the top level navigation choose any of the white buttons, and press press enter to
edit the button's Memory.
5.2 Colors
You can customizing the pre-defined programs with up to 4 colors (C1-C4). All predefined
programs, except RAINBOW take the displayed colors from a four color palette. This palette
can be defined by selecting the colors C1, C2, C3 and C4 and is shown at the top of the re-
mote control when editing the colors. For example, if PROGRAM is set to SIMPLE RUN-
NING, background color will be C1, and the color of the running pixel will be C2.
There are 3 kinds of colors available for that:
Standard Colors: red, orange, yellow, green, cyan, blue, magenta, pink, white warm,
color warm, black can be quickly chosen
Index Colors: 256 standard index colors can be chosen when selecting INDEX
COLORS. The colors are listed in Appendix B
User Colors: If this is not enough choose USER COLORS. Here, you can mix colors
out of the 3 color channels (red, blue, green)
To change colors, enter the Editor, then click any of the C1 – C4 buttons to change
their color. Leave the Editor or click the home button to save their value.
5.3 Programs of the Editor
In addition to colors, there are 20 customizable programs that can be selected when in the
Editor. The programs of the Editor use the colors defined in 5.2 to display static or moving
structures. These structures are formed out of several pixels and can stretch over several
lamps as well. A list of the 20 programs can be found in the appendix.
Note: It is also possible to let the random chaser choose colors for the programs. To use
this feature, see Chapter Appendix 10.3. Every time the Programs setting is changed, ran-
dom color chaser will be switched off!
8

Note: programs are best displayed on a multi-pixel lightsource (e.g. the AL6 series) or
stretched over a group of lamps. If used with a one-pixel lightsource (e.g. AL3-M) only one
color will be shown at a time.
Note: Not all programs use all 4 colors (C1-C4). For example the program called TWO COL-
OR STATIC uses only 2 colors so half of the pixels will be in C1 and the other half in C2.
5.4 Adjustments
The programs you have chosen can be further adjusted in fade, speed and brightness.
To adjust fade, speed and brightness, enter the Editor, then click fade, speed or the
brightness button to change their values. Leave the Editor or click the home button to
save their value.
Fade: Sets fading transitions between steps of the program in amount of the step-
time. If set to 0%, there will be no fading at all, the color will be switched at
once. If set to 100%, the color change will go smoothly from one to the other
color. Any value in between will be a mix of these two settings.
Speed: Changes the speed of the program. A time between 0,09 seconds and 9
minutes and 21 seconds can be set. This time reflects the duration of the
selected program.
Note: With the change of speed you might get the units out of sync. In order to
re-sync press the Send key or change the program (Chapter 4.1)
Brightness:You can select the Brightness Intensity or the Power Scheme of the lamp.
Both are strongly effecting the battery runtime of the lamps. Choose
INTENSITY to change the brightness of the LEDs between 0% and 100% in
intervals of 10%. Choose Power Scheme to adjust the overall power scheme of
the lamp between HIGH-BRIGHTNESS, NORMAL and MAXIMISE RUNTIME.
Attention: Battery runtime of all the Astera lamps is stated for the Normal power
scheme. Altering the power scheme will lead to different battery runtime.
5.5 Advanced Adjustments
In addition it is possible to adjust a range of parameters if the three basic adjustments are
not enough.
To change additional adjustments of colors and programs enter the Editor then press
the plus and minus buttons choose the setting you want to change and confirm with
Enter.
9

Editor Chapter 5
Stobe Speed: Adjust frequency and confirm with Enter.
Program Direction: Choose between forward (left to right), backward (right to left) and
if you want to run the effect only once or repeat it in a loop.
Program Parameter: Changes parameters depending on the program currently running.
Blower Speed: Changes the power of the blower.
Use Random Colors: When switched to YES it starts the random color chaser which
places random colors on the 4 user color channels(C1 – C4).
Each time tap-sync is pressed the 4 user colors will change.
Random Mode: Features a range of different chaser modes.
(overview in Appendix 10.3).
Random Fade: Fading time of the random chaser.
10

Targeting Lamps Chapter 6
6 Targeting Lamps
A special button has been assigned to targeting only a selection of lamps that are within the
reach of the remote control. Once one of the Target lamps options has been selected by
choosing ENTER, BACK or the HOME button you will only target those selected lamps until
another value in Target Lamps is chosen.
Target lamps …
..by GROUPS Each lamp can be set to belong to one of four groups (G1, G2, G3 or
G4). Then each groups can be controlled individually, or groups can be
linked together. If groups are linked, the program pattern stretches
over them. New lamps or reset lamps are set to group 1
Only sequential groups can be linked, for example G1+G2.
It is not possible to link G1+G3.
The GROUP setting can be altered and assigned to lamps in SETUP
using the REMOTE SETUP menu.
..by SET# Lamps can be assigned to one of 255 possible set-addresses. Also
more than one lamp can be assigned to one set #. In practice, usually
a set of lamps will be assigned one set #. Each of these sets can be
controlled individually.
It is not possible to link sets together, so that programs stretch over
them. Sets can easily be created by using SETUP->CREATE A SET.
..by TAPPING THEM By using this setting, lamps will not receive any information,
unless they are tapped. Tapped means, that their button is
pressed after they indicate that new information is available.
Usually they do this by a short white flash every 1-2 seconds.
..by TYPE If lamps of different types are used, they can be controlled by
type. For example, if you have AL6 and AL3-S setup, they can
be controlled individually by choosing their type.
..by SERIAL NUMBER If the serial number of a lamp is known, it can be addressed
directly by entering the S/N into the remote control.
11

Setup Chapter 7
7 Setup
The setup offers advanced settings that can be done before or after an event like factory re-
set, forming groups of lamps, calibrating colors and setting a keylock when giving away the
ARC2.
To enter the SETUP menu, while in the top level of the navigation press the minus
button ( - ) until you see SETUP, then confirm with Enter. If you are not sure in
which level you are, press the home button, to get to the top level.
If SETUP does not appear on pressing the ( - ) button, check the KEYLOCK setting!
Create a Set: Sets combine several lamps which can be addressed at the same time
and arranged in a preferred order to stretch effects over them. Unlike
groups, a huge number of sets (256) can be programmed and targeted
with the Target Lamps button. A set can also be applied to only 1 lamp if
this lamp needs to be targeted quickly.
Create a Chain: Chained lamps will stretch their effects and programs over several lamps.
For example the FLAG RUNNING program can send a pixel running one
AL6 until it reaches its edge, then continue on the next AL6. To allow a
smooth running along the chain, correct positions have to be assigned to
each lamp.
DMX Setup: Some Astera lamps do not have a LCD-display so the ARC2 can be used
to set them up for DMX usage. Also, Astera lamps with LCD-display might
be easier configured rempotely for DMX because their display cannot be
reached.
For additional information refer to the DMX table in Appendix 4.
DMX Address: Sets the DMX address
DMX Pixels: All pixels: Every pixel can be controlled individually
by DMX
Reduced Pixels: Pixels are combined to aachieve a
fewer pixel count for easier control. Please refer to the
manual of the specific device to see how many pixels
will be present on DMX when this setting is chosen.
One Pixel: The device can be controlled with only
three DMX channels. All pixels are combined into one.
DMX Tab: Several different DMX tables can be chosen.
RGB S RGB S..: For each pixel there are three
channels RGB and one channel stroboscope.
RGB RGB S S..: All RGB channels are followed by
all stroboscope channels.
Effect Mode Fix: The 4 user colors are controlled
by one channel per color (generates basic colors).
Effect Mode RGB: The 4 user colors are controlled
by three DMX channels each.
12

Strobe: Single: One DMX channel is supplied for
the control of the stroboscope function, all pixels
will strobe Identical. When using this setting,
DMX TAB should not be set to RGB S RGB S ..
Multiple: For each pixel, the stroboscope
can be controlled individually.
Off: Stroboscope is turned off globally.
DMX Failure: Sets the behavior of the light in case of an inter
rupted DMX signal.
Hold: The output keeps unchanged, the
last received DMX frame is displayed.
Emergency Light: If the DMX reception times
out, the light turns white.
Blackout: If the DMX reception times out,
all light turns black.
Remote Setup: Usually all configuration settings, like changing the DMX address,
chain configuration and so on is done directly on the units. This might
not be feasible if several units with the same settings have to be con
figured with the same settings or a unit is not equipped with a LCD-dis
play.
Remote Group Assigns lamps or sets into any of the 4 groups.
If not programmed, all lamps are set to group 1.
Input Select If a lamp has several input signals (for example it is
connected to a DMX cable but should be targeted
by the ARC2) the preferred input signal can be
defined
XLR DMX for the signal of wired DMX
Wireless DMX for the signal of wireless DMX
Remote Control for the radio signal of the ARC2
Standalone to keep the last input signal (for
example 1 color) until another in
put source is chosen.
Auto Automatically chooses an input
source
AC Failure Emergency Light If no AC signal is detected, the
light turns white.
No Action
Blackout If no AC signal, all light turns black.
Manual White Calibration: You can enable automatic white calibration or
manually adjust the red, green and blue levels that
are used to display white color.
SD Card Backup Keys Saves the colors and effects that have been as-
signed to the white keys.
13

Setup Chapter 7
Choose a name with the plus, minus & Enter but-
tons. Back/Tap-sync jumps to the next set of let
ters, deletes, >> stores the keys with the chosen←
name.
Restore Keys Copies the stored keys to the ARC2's memory.
Firmware update The ARC2 can be used to update the firmware of
most Astera lamps and controllers that are
equipped with a RF receiver (Antenna).
Please refer to the Firmware update manual in
appendix 10.5. for detailed instructions.
Test Radio The Test pattern Color Change allows you to test the radio frequency
range conveniently by walking away from a lamp just -16m while hold-
ing the ARC2. If the Test Radio is activated, the remote switches to min-
imum output power and transmits a color change, change every second.
If the color change works in that range, lamps and remote are ok.
You might need to move the remote around a little to avoid interference.
Radio Pin: The Radio Pin makes it possible for different customers to operate their
lamps at the same place without influencing other lamps. The 4-digit pin
can be set to a unique value and paired with selected lamps. To activate
the radio pin, choose a pin on lamps and remote control, then press PAIR
WITH LAMPS.
Factory Reset: Selecting THIS REMOTE will reset all settings including keylocks and all
MEMORY programs.
Resetting LAMPS will ask you to tap individual lamps to select which of
the lamps in range you want to reset.
For event rental companies a factory reset of the ARC2 remote should be
done after each rental job to avoid misleading settings from customers.
14

Technical Data Chapter 8
8 Technical Data
Environment
Temperature (operation) 5 °C – 40 °C
Temperature (transport) -25 °C – 55 °C (70 °C for 24h)
Relative Humidity 0 - 95%
Altitude up to 2000m above sea level
Site interior
Battery 2x 1,5V AA (LR6)
Measurements
Unit Size in mm L1 3mm x W62mm x H31mm
Unit Size in inch L7.2” x W2.4” x H1.2”
Unit Weight in gram 160g
Unit Weight in pound 0.35lb
Radio Frequency
RF Coverage Range 50m up to 300m
Frequency EU & EFTA 6 .000 MHz – 69.750 MHz
Frequency US, Canada, Australia, New Zealand 902MHz – 92 MHz
WARNING
The user must make sure, that the national regulations
allow the operation of this RF device!
If this is neglected, serious harm may occur!
1

Troubleshooting Chapter 9
9 Troubleshooting
Faulty condition Cause Troubleshooting
Units are out of sync Adjustment of the SPEED parameter
can cause deviation between the
units; also the units will drift out of
sync after a few hours.
Press SEND button or change
PROGRAM.
Units behave incorrectly Due to the vast number of settings,
one can not always predict behavior
of the units, if setup was already
done earlier.
Do FACTORY RESET on units and/or
remote control.
One/a few units don't play the
correct program, even if it was set
up earlier.
If a unit is powered up after the
light scene was setup with the
remote control, if will not work
correctly.
Press SEND button on remote
control to update the unit.
A unit is flashing in blue or other
color all the time and not accepting
any command.
It might be in BLUE MODE. Hold down the button until the
flashing stops.
One/a few units don't react on the
remote control.
You might be targeting the wrong
lamps
Check TARGET LAMPS and select
the set you have programmed the
lamps in or make sure you are
sending to all 4 groups to target all
lamps.
Units will go out of battery after only
6 hours of operation.
Some units last only hours with
COLD WHITE, if the LED POWER is
set to NORMAL. For HIGH
BRIGHTNESS the runtime may be
shorter than hours.
Adjust LED POWER and/or see
manual of the unit.
The display of a unit is showing
BLACKOUT, and there is no light
output.
Either the unit is set to BLACKOUT
mode, or DMX-FAILURE/AC
FAILURE is set to BLACKOUT and
one of these conditions persist.
Press I/O on remote control and set
to DISABLED.
Check settings of DMX-FAILURE/AC
FAILURE.
Maybe do FACTORY RESET.
Each time I press the tap-sync
buttons the displayed colors are
changing.
You have switched Random Colors
on.
Enter the Editor, select USE
RANDOM COLS, then select NO.
16

Appendix Chapter 10
1 Appendix
1 .1 Color Index
17

1 .2 Customizable Programs
Name Light Effect Used colors
ONE COLOR STATIC All pixels show the same color C1
TWO COLOR STATIC Same as ONE COLOR STATIC, but
not all pixels show the same color,
they are divided into 2, 3 or 4 parts.
C1 C2
THREE COLOR STATIC C1 C2 C3
FOUR COLOR STATIC C1 C2 C3 C4
ONE COLOR FADE All pixels show the same color, but
the color changes between all four
USER COLORS.
C1 C2 C3 C4
TWO COLOR FADE Same as ONE COLOR FADE, but not
all pixels show the same color, they
are divided into 2, 3 or 4 parts.
C1 C2 C3 C4
THREE COLOR FADE C1 C2 C3 C4
FOUR COLOR FADE C1 C2 C3 C4
SIMPLE RUNNING All pixels have C1 color, except one,
that is running over them with C2.
C1 C2
DOUBLE RUNNING Same as SIMPLE RUNNING, but
two pixels are running over the
background, in opposite directions.
C1 C2
TWO COL RUNNING Same as DOUBLE RUNNING, but
the two pixels are of different color.
C1 C2 C3
FLAG RUNNING A “flag” consisting of three color
stripes is running over the
background.
C1 C2 C3 C4
DOUBLE FLAG RUNNING Same as FLAG RUNNING, but two
flags are running in opposite
directions.
C1 C2 C3 C4
SPIRAL 4 COLORS The color of all pixels is changing
pixel by pixel from one color to the
next. If the geometry of the unit
allows it, the direction is circular.
C1 C2 C3 C4
SPIRAL 2 COLORS Same as SPIRAL 4 COLORS, but
the movement starts at both and in
opposite directions, and moves back
after all pixels are changed.
C1 C2
RAINBOW A moving rainbow is shown on the
units.
none
FIRE A flickering fire-like effect is
displayed. C1 is the background color,
randomly pixels flash and flicker with
C2.
C1 C2
ROTOR The rotor programs are much like the
FADE programs, but if the units are
of tower-like shape, then a clockwise
running rotor can be seen.
C1 C2 C3 C4
ROTOR SPLIT 2 Same as ROTOR, but two rotors in
opposite directions are running.
C1 C2 C3 C4
ROTOR SPLIT 4 Same as ROTOR, but four rotors in
opposite directions are running.
C1 C2 C3 C4
18

Appendix Chapter 10
1 .3 Color Chaser for Random Modes
RANDOM MODE[7..0]:
7..6: strobe-override mode
00: strobe not overridden
01: strobe disabled for C2, C4
10: strobe disabled for C2, C3
11: stribe disabled for C1
5..4: timeline parameters
00: at each step all colors change
01: colors change one by one
10: one step colored, next step black
11: three steps colors, one step black
3..2: color-override mode
00: colors not overridden
01: C1 is always black
10: C1 is always C1
11: C1 and C3 are always C1
1: color-wheel effect
0: color-table: 0 == color table, 1 == user colors
50: color-wheel effect, color table is used.
19

1 .4 DMX table for Effect Mode
Channel EFFECT MODE FIX EFFECT MODE RGB
1 INTENSITY
2 STROBE
3 PROGRAM
4 SPEED
5 FADE
6 DIRECTION:
0..63: FFW+LOOP
64..127: FFW
12 ..190: REW
191..255: REW+LOOP
7 SIZE:
defines the virtual size of the program in groups. For example if SIZE is set to 2
groups, only half of the program is shown on the unit.
0..63: 1 group
64..127: 2 groups
12 ..191: 3 groups
192..255: 4 groups
OFFSET:
if SIZE is set to >1 group, the units pixels can be shifted within the virtually larger
program. Increasing the OFFSET parameter scrolls the position of the unit within
the virtual large program.
9 RESTART PROGRAM:
if value is changed, the program starts again from the beginning (useful if
DIRECTION is not set to loop)
10 INDEX COLOR 1 COL 1 RED
11 INDEX COLOR 2 COL 1 GREEN
12 INDEX COLOR 3 COL 1 BLUE
13 INDEX COLOR 4 COL 2 RED
14 COL 2 GREEN
15 COL 2 BLUE
16 COL 3 RED
17 COL 3 GREEN
1 COL 3 BLUE
1 COL 4 RED
20 COL 4 GREEN
21 COL 4 BLUE
20