GRC-206 Cables

© Brooke Clarke 2008


The GRC-206 Program Pacer Speak is a system composed of three radios, VHF-FM tatical, VHF-AM and UHF-AM aircraft.  The system has provision for two operators working from a single remote control head or one operator with his own remote control.  For example one control might be mounted in a vehicle and the second control might be a few clicks away using a fiber optic cable.  It takes many cables to interconnect the system.  I'm hoping to document the cabling of the system on this page.

Cables Installed in the MT-6250B Equipment Rack

      Equipment Rack as received
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.

Cables Not in Rack

GRC-206 Cables not in

Items in second box

W?, W3. W4, W5, W6, W7, W8, W9, 3W1

Description p/n d/c
GRC-206 p/n: ? HF Gnd Wire
Cable Assembly
HF Ground?
3 socket connector to White wire with ring terminal & plug
?  ?

GRC206 p/n:
              566085-807s W3 Remote Cable
Cable Assembly
URSC Pwr & Ctrl
MS3126E10-6S (W3P2)
MS3126E10-6P (W3PX)

about 7 meters

566085-807 Sep-87
GRC-206 p/n: 566076-801 W4 HV Antenna
              wire for AM-7148 Cable Assembly, Antenna
about 1 meter
Looks like heavy duty
automotive ignition wire
566076-801 Jun-87
GRC-206 p/n: 566077-801 UHF Antenna
              Cable Cable Assembly, Antenna
N(m) (W5P2) to
N(m)RA (W5P1VHF)
about 6 feet
Nice RG-214
566077-801 Jun-87
GRC-206 p/n: 566077-802s.jpg Cable Assembly, Antenna
M39012/06-0002 KD-59-119 (W6P2) to
N(m)RA (W6P1UHF)
about 6 feet
Nice RG-214
566077-802 Jun-87
GRC-206 p/n: 566078-801 W7 Antenna
              Cable Cable Assembly, Antenna
566078-801 Nov-87

W9 GRC206 p/n: 566080802 Fiber Optic
GRC-206 W9 Dual
                Fiber Optic Cable
F/O Cable Asembly
URSC Control Only
aprox 5 m 2 Fibers
ITT Cannon, Santa Ana, Calif
FOMC 6-2W2A-001

Fully Mated 2 White Stripes Show-
Opposite Side No Stripes Show

Valtec Fiberoptic Cable

There is a longer FO cable.  More to come.
566080-802 Sep-87
3W1 GRC-206 p/n: 566084-806 3W1 AM-7148
              Audio Cable Cable Audio (in big box)



Radio Set Control C-11166-206 812085-801 Mar-88

Main DC Power Cables

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. 


GRC-206 W1 Main Vehicle Power CableThis is the cable that runs from the Vehicle battery to PDU J5 Vehicle Power.  It has a white wire that connects to the vehicle Oil Warning light so when the light is out, it's grounded and the Vehicle mode of operation is enabled.  When the oil light comes on the engine is stopped and the Vehicle mode no longer will power the system.  Switching to the Vehicle Override mode will then power the system with a warning lamp since the vehicle battery is being drained.  Three ring terminals and the oil light fitting.

Red is vehicle + 24 Volts, Green is 24 volt return, bare wire is chassis ground.


This cable runs from the Auxillary Generator set to PDU J5.  It does not have the forth wire like the W1 cable. Just the three wires: Hot, Return and ground.

eBay Wording for 1 km FO cable

Two Strand Multimode Fiber Optic Cable 1 km Length
Multiple Reels Available

This cable is in good condition but has not been tested because of missing and/or damaged connectors. All of the cable offered through this sale was manufactured by Optical Cable Corporation (OCC), Berk-Tek (Tek-Light brand) or Valtec (Phillips-Magnavox). The nominal length of each reel is 1024 meters and most reels are believed to be close to their original length. The cable being offered for sale is identical to that pictured, but the military type ITT/Cannon connectors will be removed prior to shipment. This cable can be terminated with ST, SC, and most other commonly used fiber connectors.

The OCC cable type is D02-048C-A3FB/900-MIL. The Berk-Tek and Valtec cable was manufactured to the same specifications. This is D-Series (Distribution) Military Tactical 2-fiber cable with a 4.8mm diameter polyurethane outer jacket. This is 50/125 multimode cable, with a 900um buffer coating. It should be useable in any installation that would normally use 62.5/125 cable. The attenuation and bandwidth specifications are 3dB/km and 400MHz-km at 850nm and 1dB/km and 500MHz-km at 1300nm wavelength.

The following are some characteristics of this cable, as found on the OCC web site:

The OCC web site is a valuable information resource, and features a wealth of information concerning the advantages of this tight-buffered cable, as well as additional information on the construction of the cable and its specifications.

Reels of cable that have been tested and are guaranteed are usually available at a price of $500 per reel. Please check my other eBay listings.

Patents & Related Info

Just looking now, these may or may not be applicable.  There are many more Fiber Optic Connector patents by ITT.
4090778 Terminating optical fibers and optical fiber connector, Phillips & Archer (ITT), May 23, 1978 - watch bearing jewels
4140365 Fiber optic cable connector housing (ITT)- plastic snap in, not this one
4146300 Fiber optic eccentric connector (ITT) - not this one
4205898 Optical fiber connector (ITT) - triangular clip on each fiber for alignment, not this one
4168108 Fiber optic connector (ITT) - single fiber to mixing device, not this one
4711752 Method and apparatus for molding fiber optic connector ferrule (ITT) - to keep fiber on center line, maybe related
4828510 Connector latching arrangement (ITT) - a way to make a rectangular connector with many fibers
5230032 Abutting tips fiber optic connector and method of making same (ITT) Jul 20, 1993 - uses ramp and hook to hold mating parts, not threads like this one

ADP002558 Design, Fabrication and Testing of a Ruggedized Fiberoptic Cable, Corporate Author : VALTEC WEST BOYLSTON MA, 17 NOV 1983,
Abstract : This paper presents the design and manufacture of a small size, lightweight, all dielectric cable suitable for easy deployment and recovery in cross-country terrain. Intended as the data and communication link between a battlefield radio station and a jeep-mounted radio system, the cable is composed of two optical fibers twisted together, around which are applied two contrahelically wound layers of Kevlar yarns, an inner jacket, two more contrahelical layers of Kevlar yarns, followed by an outer jacket.


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