MT-6250B/GRC-206 Program Pacer Speak System Rack

© Brooke Clarke 2008



16 Jun 2009
GRC-206 FAC
                System

See System 9 Jan 2009
GRC-206 9
                Jan 2009

MT-6250/GRC-206 Equipment Rack Partially filled GRC-206 System
                Rack MT-6250B Right Side
MT-6250B/GRC-206 Back 2
Front
Input Power Conn, MT-1029 for RT-246
Back
Background
Versions
    HF Pallet Upgrade
    Description from gaming web site
    FM 3-51.3
New Old Stock
Remote Mount
Bite Audio Interface
Prime Power
Vehicles
First Power
Second Power
ME-548/GSM-317 Fiber Optic Power Meter (Not GRC-206)
Related Web Pages - including other GRC-206 components
Sources of GRC-206 Items
Links

Background

The GRC-206 Program Pacer Speak is a collection of radios used for Forward Air Control.  This rack holds the radios and related equipment in a size that's compact and fits a HMMWV or other military vehicles.  I cut the pallet that it was shipped on in half, leaving the center 2x4.  This keeps it up off the concrete floor and makes it a little higher for ease of access.

When the GRC-206 is mounted in the M998 HMMWV it's called the MRC-144.

The system draws up to 1500 Watts at 24 VDC or 63 Amps.  The MEP-802 diesel gen set is only rated to supply 16 Amps from it's NATO slave battery charging connector, but is rated for 5,000 Watts on the 60 Hz AC output.  The implication is that the M455-1 can convert the AC into 24 VDC to power the system.  The connector pins on the M455-1 are not as large as the input connectors on the SB-4151 but many of them are connected in parallel to carry high currents.

Book: Danger Close: Tactical Air Controllers in Afghanistan and Iraq (Williams-Ford Texas A&M University Military History Series)
Makes the case that when the FAC is within eye sight of the target the precision weapons work so well that ground forces are not needed.

Variants/Upgrades

The first four versions were designed at the start. (V)1 and (V)3 have crypto and (V)2 and (V)4 do not have crypto.   The GRC-206 system specific boxes were designed to allow for optional crypto and/or Have Quick operation.
Some speculation as of Dec 2008

(V)1
(V)2
(V)3
1987
(V)3+
(V)4
(V)5
1999
(V)5
(V)6
(V)?
HF
URC-113
URC-113 URC-113 PRC-138 URC-113 URC-113 URC-113
URC-113 PRC-138
VHF-FM
RT-246
VRC-46
RT-246
VRC-46
RT-246
VRC-46

RT-246
VRC-46
SINCGARS
VRC-91A
ANDVT (FAS)
SINCGARS
VRC-91A
ANDVT (FAS)
SINCGARS
VRC-91A
ANDVT (FAS)
SINCGARS
VRC-91A
ANDVT (FAS)
Crypto
KY-65
KY-57 (3)
No
KY-65
KY-57 (3)

KY-65
KY-57 (3)
?
No KY-99A
KY-57 (2)
KY-99A
KY-57 (2)
Have Quick
No
RT-1319
No
RT-1319
Yes  I
RT-1319B

Yes  I
RT-1319B
Yes  II
RT-1319C
Yes  II
RT-1319C
Yes  II
RT-1319C
Yes  II
RT-1319C
SATCOM
No
No No
No No
No

UHF DAMA (FAS)
RFO
No
No
Yes

No
Option
Option Option GPS
Weight (lbs)
368
308
418






Prime Pwr
MEP-025
Gas DC Gen
MEP-025
Gas DC Gen
MEP-025
Gas DC Gen

MEP-025
Gas DC Gen
MEP-802
Diesel AC Gen
MEP-802
Diesel AC Gen
?

Inverter ?
No
No
No

No
?
? ?

Rack
MT-6250?
MT-6251?
MT-6250A
MT-6250B
MT-6250 MT-6250  MT-6250E
 MT-6250E  MT-6250E
? The URC-113A uses the RT-1444A which has ALE capability.  But the AM-7148 does not look like it can handle ALE, hence the need for the PRC-138.
(V)3 systems were converted into (V)5 systems in Texas by replacing the VRC-12 radio with SINCGARS radios and replacing the BITE/Audio Interface box.
The manuals for (V)5 and (V)6 show the same BITE/Audio Interface box and so far do not show how the remote can select the VHF-FM channel.

GRC-206(V)3

GRC-206(V)3

 HF Pallet Upgrade Jul 27, 2009 RFQ

This would replace the HF power amp with he Harris 150 Watt RF5800 amp and the 5328 Coupler.  A UHF SATCOM antenna is included in this RFQ so the Diplexer may be related, but how with an HF radio?

CLIN

Description

Quantity

0001

GD-1813                       Multi-band vehicle Antenna

1 EA

0002

12020-1460-A025         Cable Assemly, PA To Coup.Ct

 

1 EA

0003

10181-9824-025            C. Assembly PA/RF-382 Cplr.

 

1 EA

0004

10181-9824-250           COAXIAL CABLE (M17/74-RG-213) ASSY

                                     CBL W TYP.N MALE CONN

1 EA

0005

RF-5800H- V001          150WHF PA

1 EA


0006

RF-5382H-- CU001      150W HF ANT. COUPLER

 

1 EA

0007

SB-V16F                      SPRING BASE 16 FT HF WHIP ANT

1 EA

0008

RF-5384VM-01            HF ANT. COUPER SHOCK MOUNT FOR RF-

                                     5382H ANTENNA

1 EA

0009

10369-7211-25            CABLE ASSY, N TO BNC

 

1 EA

0010

RF-292-01                    UNVERSAL ANTENNA MOUNT FOR SB-V

                                     SERIES FEED THROUGH ADN

1 EA

0011

10564-2420-01            DUPLEXER (HARRIS)

 

1 EA

0012

PE7139                        MANUAL RF COAX SWITCH

1 EA

0013

AV-2091-0-00              UHF SATCOM ANTENNA

 

1 EA

0014

10181-9826-020          DC POWER CABLE, HARRIS RF-5800H-V001

 

1 EA


Description from gaming web site

This description of the varients might be wrong or incomplete
GRC-206(V)1.  Includes provisions for user-supplied COMSEC devices.
GRC-206(V)2.  Does not include these provisions, but space is available for other user-selected components.
GRC-206(V)3.  Is identical to the (V)1 except that electronic counter-countermeasures (ECCM) are pro­vided within the UHF radio set.
GRC-204(V)4.  Combined with the Meteorological Measuring System and ancillary equipment, this model is installed in a HMMWV to form the TSQ-198 Tactical Terminal Control System (TTCS) for the US Army.  PSN-11 GPS capability is also provided.
GRC-206(V)5.  Modifies the (V)3 to incorporate the SINCGARS radio and the USC-43(V) Advanced Narrowband Digital Voice Terminal (ANDVT).  Built-In Test (BIT) functions were also enhanced.
GRC-206(V) P3I.  As part of preplanned product im­provements, the GRC-203(V) can accommodate a PSC‑5 enhanced man-pack UHF transceiver, either as an addition or by replacing an existing component (such as the RT-1319).  Improvements include UHF/FM SATCOM and DAMA, 8.3 kHz channel spacing in VHF/AM for ICAO air traffic control in Europe, TDMA in VHF/AM for US civil (Federal Aviation Administration) air traffic control, SATURN ECCM in UHF/AM for NATO, expansion of the UHF band to 512 MHz for civil command and control, and video compression imagery.

FM 3-51.3

While reading FM 3-52.3  (learning about bedwindow gingerbread procedures) it mentiones that the AN/TSQ-198 is a HMMWV mounted ATC system consisting of the:
VRC-83 - VHF AM low and UHF AM aircraft bands
VRC-90F - VHF low FM
ARC-220 HF (Ground version is the VRC-100) from FAS this is a Nap-Of-The-Earth HF system:
AN/ARC-220 photo
          from FAS
The AN/ARC-220(V) and its ground version, the AN/VRC-100(V) will replace the AN/ARC-199(V) and AN/VRC-86(V) respectively. Secure communications will be achieved through the use of the KY-100 Crypto Set. The AN/ARC-220(V)1 consists of three line replaceable units; a Receiver-Transmitter (RT), a Power Amplifier Coupler (PAC), and Control Display Unit (CDU). The AN/ARC-220(V)2 is for bussed (1553) aircraft and consists of just the RT and PAC. The AN/VRC-100(V)1 consists of the three LRU's housed in a metal casing along with a power supply and speaker. The AN/VRC-100(V)2 is the AN/VRC-100(V)1 mounted on a HMMWV along with associated brackets and antennas. The AN/VRC-100(V)3 is for Echelons Above Corps and consists of the AN/VRC-100(V)1 with the AS-3791/G Broadband Antenna.

Timetable

 

1981

Magnavox awarded production contract

Late

1983

First units delivered

Mar

1991

Last production contract awarded for US Air Force

Sep

1993

Contract awarded for retrofit/upgrade to (V)5 standard

 

1994

GRC-206(V)4 selected for US Army TTCS program

 

1995

Corporate acquisition transferred GRC-206(V) business to Hughes

 

1997

Hughes absorbed into Raytheon Systems Company

Sep

1999

Raytheon received US$25 million contract for Foreign Military Sale of GRC‑206(V) to Greece

New Old Stock

MT-6250 in Military
      packaging bag New Old Stock

This rack was New Old Stock.  The packing bag label:
FSCM 37695 P/N 812084-803
1 EA EQPT MTG RACK
s/n AH0036
INCLUDING:
1 EA P/N B812132-801 FM BITE
s/n AH0039
1 EA P/N 5810-01-050-7184
KY-65 MOUNT
1 EA P/N 5820-00-893-1323
VH-FM MOUNT (MT-1209/VRC)

The standard four foot square pallet gives some idea of size.





As Received

Front View


MT-6250/GRC-206
      Equipment Rack as received
In the photo at left it can be seen that the MT-6250B rack comes with all the equipment mounts and a lot of the system cabling.

Top Left VRC-83: 5 connectors
Top Center: O-1814: 2 connectors
Top Right: URC-113: 4 connectors
Middle Left: two KY-57: 3 connectors each
Middle Center: KY-65: 2 connectors
Middle Right: SDU: 6 Conn & PDU: 5 conn + rear input
Lower Left VRC-83: 5 conn
FM Bite/Audio Interface box: AS-1729, VHF-FM, SDU
third KY-57: 2 conn.
Lower Right: VHF-FM: 4 conn.






Back View

MT-6250B/GRC-206 Back
      Side as receivedAt the middle elevation left side is a box that connects to the back of the Power Distribution Unit (PDU) and has vehicle DC power cables for each of the system boxes.


37 7/8" wide x 16 1/8" deep x 30 3/8" hi.
There are two folding handles on the left side and two more on the right side.  I think that's for four men to each have a handle if the rack was loaded, or a two man carry empty.  The two man empty carry is because of bulk more than weight.

The HF radio sits in the upper left corner of this back view.  There is a cable clamp on the back of the rack just below where the AM-7148 power cable connects (just above the PDU location).

The box at the left center is behind the SB-4151 PDU and the cables out the back are the DC power cables feeding most of the rack equipment.  The exception is the front panel cable to the RFO.







Remote Mount p/n 812805-801

Mike Murphy has these as New Old Stock (Sep 2009).
GRC-206 Remote
                Control Mount p/n 812805-801 The Label:

CAGE 37695 p/n 812805-801
BRACKET, MOUNT
    1 EA
F04606-89-D-0110-0003
A/A   5/93
SER NO. ____________________ (no serial number on blank line)
The brown paper is special anti-corrosion treated.
GRC-206 Remote
                Control Mount

GRC-206 Remote
                Control Mount
Mount with C-11166 Universal Remote System Control  URSC

There are two rows of 0.36" wide mounting slots.  Three slots per row.
In each row the slots are 5.25" center to center
The rows are 4.00" center to center.

The bottom mount lip overlaps the battery cover and so you need to remove
the remote in order to change the batteries.

The rectangular hole in the mounting plate clears the passenger side dash mounted grab handle in the M151 Jeep.

System 9 Jan 2009

There are two Remotes, but only one FO cable so the second one can not be connected.
The Power Supply is maintaining the Cyclon back up batteries inside the RFO.  The green lamp above the power switch is on and the third lamp to it's left (under the cable) is Red indicating SET CLOCK.
Two HYP-57 Wire Line Adapters are filling the KY-57 slots for the aircraft radios.
Upper left has a couple of battery boxes from the HYP-57s, too long to leave on.
KY-57 filling the slot for the VHF-FM radio.
SINCGARS VRC-87 sitting in the VHF-FM radio slot, but it will not operate unless the MT-1029 is removed.  But the AM-2060 with a PRC-77 would fit the MT-1029 and you could connect the BITE/Audio Interface and the audio so the remote would work with it.  Although there is only one channel.
The M455-1 is just sitting at the lower left corner.  It's a little shorter than the RT-1319.

Bite Audio Interface

NSN: 5895-01-192-1190
p/n: 812132-801

MT-6250B Bite
              Audio Interface Front
MT-6250B Bite
              Audio Interface Back
MT-6250B Bite Audio Interface Front
MT-6250B Bite Audio Interface Back
The FM Bite box marking AS-1729 suggests that this rack was designed to hold a VRC-12 series radio instead of a SINCGARS radio.

Also the mount in the lower right corner looks like the MT-1029 which would hold a VRC-12 series receiver like the RT-524 w/speaker or RT-246 with 10 remote controled channels.  There is no J-3513 in the MT-1029 like in normal VRC-12 series radios with the KY-57 so it's function must be done in the BITE/Audio Interface.

It's looking like the RT-246 that has 10 channels that can be selected remotely is what went into this rack.  That means that the SDU and/or BITE/Audio Interface contain circuitry that allows serial control (since it must be done over the fiber optic link) of the channel.  This serial protocol may match the SINCGARS serial channel selection protocol?

Why the BITE/Audio Interface has the VHF-FM antenna connection is also a mystery.

Connectors

J#
Label
Function
J1
AS-1729
RF to/from AS-1729 Antenna
J2
VHF-FM
RF to/from radio
J3
SDU
"Y" cable to SDU and REMOTE on radio
J4
VHF-FM X-Mode & (ReTrans or Audio) on rradio
J5
KY-57
KY-57 RADIO connector

In a crypto system the handset is connected to the KY-57 and so the PTT for the radio comes from the KY-57, through the BAI box  then to the radio.
When no crypto the VHF-FM audio cable from the SDU is connected to the Retransmission connector on the radio.
There is no connection to the radio AUDIO connector in the system.

The RT-246 or RT-524 has the internal crypto switch left in the plain text position for both unsecured and secured coms.    When the BAI box is connected to the radio it makes the same connection that the internal switch would have made.  That way it's easy to unplug the BITE box to get back to plain text transmissions without opening up the radio.

BAI J2

Pin
Signal
SDU-J11
A
Ground
U
B
CT or PT
Z
C
BITE
Y
D
+12 V
X
E
DC Rtn
W
F
Spare
/E

BAI J4

Pin
BAI Signal
RT-246

X-Mode
Audio
A
ground
F
-
B
TR Relay
K
-
C
X-Mode to Tx
G
-
D
PT in from Tx
E
-
E
PT out to Rx
C
-
F
X-Mode in from Rx
A
-
G
Tone K401-5
D
-
H
Tone Mode
J

J
Mic Audio
-
D
K
Un Muted Audio
-
B
L
ground
-
A

BAI J5

Pin
Signal
KY-57 RADIO
A
PT Out
K
B
Squelch Control
T
C
CT In
D
D
CTOIP
E
E
PT In
M
F
Rx PT
C
G
Rx CT
A
H
PTT
S
J
PTO Rtn
L
K
ground
G

The BAI replaces the J-3513 and by sampling the RF during Tx generates a bit of BITE.

Prime Power

System versions (V)1 through (V)4 were powered by the MEP-025A 1.5 kw gas DC generator.  It weighs 121 pounds dry.

Later versions use the MEP-802A 5  kw 60 Hz AC diesel generator skid mounted tatical quiet It weight 800 pounds dry.  Since the DC output from this generator intended for battery charging can not supply enough current for the GRC-206 system an inverter is needed.  The M455-1 accepts either DC or AC inputs and provides 28 VDC output as one of it's outputs.  But the connector contacts look too small for the 50 Amps needed by the GRC-206.  So it's not clear how the MEP-802A can power the GRC-206?

Vehicles

System versions (V)1 through (V)4 were intended for mounting on either the M151 Jeep, M113 Armored Personel Carrier.
The MT-6250 is 38" wide at the bottom 9excluding the ears at the top) and just fits between the rear wheel wells in the M151 Jeep.
The Remote Mount bracket is designed to go over the passenger dash mounted grab handle.
The Generator and it's fuel tank would be on the 1/4 Ton M-416 trailer.

IDF M151

This appears to be a custom rack(not the MT-6250) and uses radios made in Israel.
M151A2 GRC-206 IDF
IDF GRC-106 in M151 view of Remote
                Control
GRC-206 in M151 view of Remote Control
Photos courtesy of Chance Wolf



AS-1729
VHF-FM Ant
 (Not enough antennas??)

HF Whip Antenna
UHF-AM Ant


Custom PDU
Custom SDU
VRC-240T
PRC-660 UHF-AM
AM-2411TG RF Amp
FO Cable spool

PRC-174 HF

RT-246 VHF-FM


VRC-240T
PRC-660 UHF-AM
AM-2411TG RF Amp
PRC-174 HF
AM-1760 or AM-4760 RF Amp


C11176 URSC
(passenger side dash over grab handle



Later systems are typically mounted on the M998 HMMWV.

First Power

GRC-206 First
        PowerMain Power Input

The main input connectors has a 24-22 Insert and pins that are 0.144" diameter. 
The cap is marked 8544 Cannon  CA121003-908.
Pin A is +24 Volts and pins B & C are ground.  Maybe pin D is also hot? That way the two top pins would be hot and the bottom pins ground.

SB-4151 PDU

When 30 volts is applied to A and D the RFO receives power no matter how the SB-4151 switches are set.  Notice that J3 is not in the box with the lower switch, J1 & J2, i.e. it's hot all the time.
But the green power light does not turn on when the mode switch is at M-G or Vehicle, but only in Vehicle Override as shown at left.

The power connector on the back of the AM-7148 is only hot when in the Vehicle Override position. 

The input voltage in the photo is 29.8 yet the voltmeter on the PDU is reading about 20.  When the mode is switched from Vehicle Override to Vehicle the green lamp slowly (maybe 5 seconds) dies out like there was a big capacitor discharging.

Maybe this PDU is defective?

The row of aux pwr banana jacks are switched on or off independent of the Master reset switch.
Jacks J1 & J2 switch on or off independent of the master power switch.

The current on the power supply is caused by charging the batteries in the RFO.

AM-7148 URC-113

The RT-1444 is not yet installed so the remote control cable is laying in front of the AM-7148.  The RT-1209 is installed.  But when the mode switch is set to STATUS or MODULE TEST nothing happens, as if it was not getting any power.

Remote

Both the PWR and FO cables are connected, and there's one internal battery, but when the BATTERY switch is turned ON the red lamp comes on, the fault tone is heard and the status display shows Cable Fault.  It's as if it was not working.

Second Power

After opening up the SB-4151 it was discovered that J4 the Vehicle input jack MUST have pin D grounded in order for the contactor in the SB-4151 to actuate turning on the system.
Once that's done then the AM-7148 does the module test and the Remote no longer shows the cable fault error.  Also the remote allows keyboard entries, like setting a frequency, but since there's no radios now connected gives an error beep when you try to enter the frequency.

16 Jun 2009 Photo

The RT-1319 is in the upper left UHF AM military air band position.  But the RF amp is still missing.
The RT-246 is in the lower right VHF FM military ground and air position.
All three KY-57 slots have been filled, but need to add internal jumpers to pass clear text.
The M455-1 needs some unknown front panel jumper or wiring to get it to turn on.
Have a linear power supply that should be able to power one radio and cable with plug to fit SB-4151.

ME-548/GSM-317 Fiber Optic Power Meter (Not GRC-206)

I bought this in the hope that it would work with the dual fiber optic cables in the GRC-206, but the dual fiber optic connector is larger than for the GRC-206 and is for the GSM-317 Test Set.  The other part of the test set is the T-1514/GSM-317 Optical Transmitter.  (see: TM 2000-OD/2C)  But here's some photographs of it.


ME-548/GSM-317 Fiber Optic Power Meter

ME-548/GSM-317 Fiber Optic Power Meter
Shown with GRC-206 remote FO cable connector.
ME-548/GSM-317 Fiber Optic Power Meter
One or both of the center FO receiver ICs are bad.
ME-548/GSM-317 Fiber Optic Power Meter

ME-548/GSM-317 Fiber Optic Power Meter

ME-548/GSM-317 Fiber Optic Power Meter



Related Web Pages

GRC-206 Program Pacer Speak
C-11166 Universal Remote System Control  URSC - GRC-2006 Dual Remote Control
C-11169 Signal Distribution Unit SDU
SB-4151 Power Distribution Unit PDU
O-1814 Reference Frequency Oscillator RFO
PRC-104 Manpack HF radio
AM-7148 HF RF Amp
RT-246 VHF FM Radio
RT-1319 VHF AM Aircraft Radio
RT-1444 Remote Control adapter for the RT-1209 (PRC-104)
KY-57 Transmission Security Device for VHF and UHF radios
KY-65 Narrowband Secure Voice Unit for HF radios
GRC-206 Cables 
VRC-83 Vehicle version of PRC-113 with RF Amp Aircraft radio covering VHF-AM and UHF-AM bands
There are three versions of the RT-1319, the first did not use "Have Quick", the second used the first version of Have Quick and the third used Have Quick II.
The RFO is in this system specifically to supply the RT-1319 with TOD for Have Quick, so this system uses either of the Have Quick versions of the radio.
AM-7176 - Aircraft VHF & UHF Power Amp
HMMWV Hummer 1 ¼-Ton, 4X4 military vehicle - M998 used for MRC-144
AT-1011 HF Whip Antenna
AS-2259 HF NVIS Antenna
AS-1729 VHF-FM Ant
AS-3588/GRC-206 VHF-AM & UHF-AM Antenna
MT-1029 (lower right mount for VHF-FM)
VRC-12 Series Radios RT-246 VHF-FM Radio
M455-1/GRC-206 Power Source (but pins are only 0.063" dia) How to make this power supply work let me know. (maybe it has bad caps?)
EMCU 116 12 VDC Input 24 VDC Output - The pins on this supply are the same size as the GRC-206 input pins and so may be more suitable to power it.
(V)5 Systems replace the VRC-12 series radio with SINCGARS & Replace the KY-65 with a KY-99A
SINCGARS VHF FM tactical radio, RT-1439
KY-99 Advanced Narrowband Digital Voice Terminal (ANDVT) Family (FAS web site)
FM Bite/Audio Interface -
Magnavox 812067-801  HF Antenna Mount - holds the AT1011 HF antenna
MEP-025 DC Generator  NSN: 6115-00-017-8236 (aka: JHGV1.5A)
(not the 6115-00-889-1446 MEP-015 AC gen set) 
have: TM 5-6115-323-14, TM 5-6115-323-24P
28V @ <= 53.5 Amps (1.5 KW)
PP-1104 AC power supply
        Input:    115 @ 24 Amps (NOTE: Exceeds normal household 15A circuit capacity)
                    230 @ 12 Amps
                    60 Hz AC
      Output:   "12 Volt" 11.5 to 17.5 VDC (100 Amps @ 14 VDC)
                    "24 Volt"  23  to  35    VDC (  50 Amps @ 28 VDC)
PP-6224 only 30 Amps at up to 30 Volts, maybe enough to run one radio and the rest of the system.
J-4024/U GRC-206 Interconnecting Box - Allows connecting a DLED ((Dedicated Loop Encryption Device) to either of 2 transmitters and either of 2 receivers and TTY machines.
PSC-2 Digital Communications Terminal (DCT) provides burst transmission capability
Model 1040 ALE Modem - RT-1444A - ALE version of remote adapter RT-1444.  Used in the GRC-206(V), URC-113A. Only provides ALE when used with the GRC-206(V), not front panel ALE.

Sources of GRC-206 Items

Mike Murphy
eBay seller lonym
eBay seller art-in-part
eBay search for GRC-206, URC-113, VRC-83, VRC-87, RT-1319, VRC-89,
Columbia Electronics - Paul Keys has many of the system parts and supports it to government buyers
William Perry - good source for connectors

Links

Ground Forward Air Controlc.1963  F-105 (14:46 video) F105,

A Close Call - "Airmen like Senior Airman Courtney Hinson, a terminal attack controller, are entrusted with an MRC-144 weapons system — a half-million dollars in communications equipment housed within a Humvee. As part of the 18th Air Support Operations Group, supporting 18th Airborne Corps, Hinson and his comrades are responsible for keeping their systems and the mission running. And testing frequencies is part of knowing the system."

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page created 25 Dec 2008.