Introduction

Most of the documentation on the VIC-1 equipment is in the VRC-12 Series Radio manuals so I have combined them on this web page.
Since the MT-1029 Mount, which is a part of all VRC-12 series radio systems, is also used with other radios it's on a seperate web page that also has information on the VINSON compatable versions of the VRC-12 system.

VIC Background

VIC-1 System Boxes

AM-1780, AM-1780A, AM-1780B Amplifier

J509 & J511 for use with C-2299 Radio Relay Box
J501 to "A" radio
J510 to "B" aux receiver
J503 to "C" radio -or- J508 to "C" aux receiver
J504 to commanders C-2298 Control Box
J506 & J507 to crew members control boxes
J505 to drivers Control box or a crew members control box

C-2296 Outside Control Box

Connects to C-2297 Drivers Control Box.  It has volume control and a RAD TRANS-INT switch and permanently connected handset with a coiled cord.  Also a receptacle for connection to an external call lamp.

The metal box that holds the C-2296 is NSN 5965-856-6219 "Handset Box Assy" It has an indicator light pointing up on the front surrounded by a metal shield.

TM 11-5820-401-35-6, Direct Support, General Support, and Depot Maintenance Manual Including Repair Parts and Special Tools List for Control, Intercommunication Set C-2296/VRC (FSN: 5820-892-3337), Nov 1973

TM-9-2350-230-12 M551A1 152mm gun.

C-2297 Driver's Control Box

Looks very similar to the C-2298 but has a added SIG-EXT-OFF switch and indicator light that are both associated with the C-2296 Outside Control Box.  When the switch is set to SIG the call light on the external box is turned on (similar to ringing a phone, but you could not hear this phone ring).  When in the EXT position the Outside Control Box is connected into VIC-1 system.  When in the OFF position the Outside Control Box is disconnected from the VIC-1 system and the outside PTT switch lights the Indicator lamp on the Driver's Control Box.

C-2298 Commander & Crew Control Box

The switch positions are:
All - listen to A radio, B aux rcvr & C aux rcvr, Talk and listen on intercom, Tx on A radio (only when no intercom traffic).
A -listen to A radio, Tx on A radio, talk and listen on intercom (radio or intercom is selected by switch on haadset).
Internal Only - talk and listen on intercom
B - listen to B aux rcvr, Tx on A radio, talk and listen on intercom
C - listen to C radio or C aus rcvr, Tx on C radio, NO intercom function.
The function of this box is slightly different depending on how it's connected to the AM-1780.

C-2299 Radio Relay Control Box

This box can be used with the AM-1780 or used with just radios and no AM-1780.  For example if a retansmission system was in a jeep or HMMWV there would be no need for the AM-1780 so just the C-2299 would be used.

J701 Left-Front-Bottom	J703 Bottom-Front J704	Right-Front-Top J702

The left "RAD TRANS" switch controls which radio you transmit from using a handset or mike connected to one of the C-2299 audio connectors.  The right "RETRANS" switch turns retransmission either ON or OFF.  The VOLUME control only effects the loudness of a locally connected handset or speaker.

Note ONLY  the radio connected to C-2299-J701 is supplying power the the mike amp in the C-2299.  So if you want to use a handset connected to C-2299-J703 or J704 the radio connected to J701 needs to be powered.  There is no DC  path from J702 to the mike amp so even though you connect a powered radio to J702 and set RETRANS off and RAD TRANS to 2, you will NOT be able to get mike audio to the radio.  You will however be able to key the radio.  This is normal and does not indicate a problem with the C-2299. 

A simple modification would be to put a couple of series diodes from both J701 and J702 to the mike amp so either side would power the mike amp.

For my taste the handset speaker volume is low when connected to either J703 or J704 with the volume control all the way to max.  This may be due to differences in the RT-246/RT-524 and the PRC-77 or GRC-213 audio out signal levels or impedance.  R703 in the C-2299 is a 150 Ohm resistor that is the impedance load for either radio's audio and may be too low a value.  This also may be why the audio coming from the transmitter seems weak.

Note: A long time ago when 1/4" phone plugs were common it was easy to have switching that was activated by inserting/removing the plug  into/from the jack.  I used this switching to disable loudspeakers in radios and TVs when headphones were inserted into the jack.
When the military went to the U-77 and now the U-229 type audio connectors you can no longer use mechanical means to detect that the audio accessory is connected.  Instead a small current limited DC voltage is output along with the audio signal and the current is sensed in the PRC-68 family of radios to know when to mute the internal speaker.

The C-2299 does not have this audio accessory sensing circuitry and so might be over loading the audio line.

Maybe this is why there are not many of these boxes around?

Retransmission

Retransmission is similar to a repeater, but with a huge difference.  Retransmission is a two way system whereas a repeater is a one way system.

Cross Band Retransmission

One of the big advantages of retransmission is that it allows cross band communication.  For example if a VRC-64/PRC-77 VHF low band radio is connected to a GRC-213 HF radio using the C-2299 Retransmission box.  Then someone within range of the VRC-64 can use a hand held PRC-126 radio to make simplex contacts on HF radio.

The California Highway Patrol uses a retransmission system in their patrol cars.  The radio link from base to car is by means of a VHF low band.  The officer carries a VHF high band radio when out of the car that has the VHF low band base station retransmission linked.

Note that the power supply to the system only needs to have current capacity of the highest current transmitter plus the other band receiver.  Never are both transmitters on at the same time.

I wonder if there are other radio systems that have the VIC-1 connector that could be used for other bands?

C-2742 Channel Selection Box for RT-246

C-10374 VINSON Radio Relay Box

Cables

There are two types of cables used with the VRC-12 series vehicle systems.  The 9 and 18 contact MW series.  In addition there are the DC Power cables as shown on the MT-1029 page.

9 Contact MW Series

MW20F(M)B00

18 Contact MW Series

MW10M(M)D11
MW20F(M)D00

VRC-12 Series Radios

Legacy radio system retired from Army Guard
Nov 20, 2008
BY Staff Sgt. Jon Soucy 

ARLINGTON, Va., (Army News Service, Nov. 20, 2008) -- After more than 50 years in service, the venerable AN/VRC-12 series radio was retired from the Army National Guard in a ceremony Nov. 18 at the Army National Guard Readiness Center.

For many, the retirement is symbolic of many other changes that have taken place within the Guard over the past few years.

"This is really a symbol of us transforming to an operational force," said Maj. Tony Caldwell, the Army National Guard battle command team chief. His team oversaw the phasing out of the '12'-series radio systems.

First introduced in the 1950s, the 12 series radios were used extensively in Vietnam and retired from the active component in the late 1980s in favor of the Single Channel Ground and Airborne Radio, more commonly known as the SINCGARS, said Caldwell.

The 12 series radios were still common in the Guard and Reserve in 1991 during Operation Desert Storm. And for those called to active duty for that conflict, once on the ground in the Middle East, communications became a problem.

"It was difficult for those with the older radios to talk with those using the SINCGARS," said Caldwell.

Throughout the ensuing 17 years since the Gulf War, the SINCGARS radio was phased into the inventory of Guard and Reserve units, but it wasn't until recently that all remaining 12 series radios were replaced, said Caldwell.

The replacement of the radios also represents a change in the way units are supplied with equipment.

"There's been a real change in the last few years and if you hadn't been around before, you wouldn't appreciate it," said Col. Harold Greene, deputy director for material at the Department of the Army.

In the old system, there was a tiered readiness level with certain units getting newer equipment first, said Greene. "I can tell you absolutely, today, we don't do that in any of the components."

Now, said Greene, units are equipped based solely on their Modified Table of Organization and Equipment, the document that lists out what equipment and people and how many of each units should have, regardless if the unit is active or reserve component.

"Certainly, as we go through deployments in support of the Global War on Terrorism, we don't distinguish between components in how we use those troops (in those units)," said Greene.

The SINCGARS has many improvements over the 12 series radios such as a greater range, greater battery life and the ability to hop between frequencies, which results in greater security of radio transmissions.

But, for many, the 12 series will always occupy a certain place in their heart.

Brig. Gen. Leodis T. Jennings, special assistant to the director of the Army National Guard, said his greatest memory of the 12 series radio was using it while attending the Primary Leadership Development Course as an E-4 at Fort Lewis, Wash.

There, students used 12 series radios as they rotated through positions in a squad while on patrol.

"It (radio operator) got to be the position I hated the most," said Jennings. "Every time the patrol leader did something or went somewhere you came running with this radio on your back and you would hand it to him and it didn't work. And he would say, 'What have you done to the thing?'

"And, I don't recall ever doing anything to it. More often than not it didn't work. You were carrying extra batteries and it was heavy. I don't know how long the batteries were supposed to last, I think we were told eight hours, but if you had one that lasted two hours you were doing good."  (Brooke:  Note this is not correct the VRC-12 radios are NOT man portable!)

Short battery life and a penchant for overheating are things that stick in the minds of many who remember the radios, said Caldwell, who as part of an artillery unit used to have his Soldiers place wet sandbags on top of the radio units to help keep them cool.

Despite those obstacles, Guard members still met the mission. "Even though this was a capable piece of equipment, it was not the best radio, but we in the Guard made it work," said Jennings.

And for those currently serving and using outdated equipment, Greene says be patient.

"Hopefully, we've now set the system up so that it won't be these relics of the past, of my past as a young officer, that hang on out there in the farthest reaches of the National Guard. And that we've got everyone modernized ... across the entire force," said Greene.

(Staff Sgt. Jon Soucy writes for National Guard Bureau)

TF 11-3305 Radio Set AN/VRC-12, 1963 - RT-66, RT-67, RT-68 are replaced by VRC-12 which consists of: RT-246, RT-524, R-442
another link to the same file in two parts.
Radio Set AN/VRC12 pt1-2 1963 US Army Training Film 
Radio Set AN/VRC12 pt2-2 1963 US Army Training Film

The "VRC-12 Series" of radios is is the shorthand way of saying each of the following vehicle radio set names.  These radios are supposed to have an annual alignment  Ref June '94 PS mag 499 pg 5 and TM 11-5820-401-20-1 Paragraph 3-5.

	VRC-12	VRC-43	VRC-44	VRC-45	VRC-46	VRC-47	VRC-48	VRC-49	VRC-53 GRC-125	VRC-64 GRC-160
RT-246	1	1	1	2	0	0	0	0	-	-
RT-524	0	0	0	0	1	1	1	2	-	-
R-442	1	0	2	0	0	1	2	0	-	-
PRC-25	-	-	-	-	-	-	-	-	1	0
PRC-77	-	-	-	-	-	-	-	-	0	1

I've shown the VRC-53/GRC-125 (PRC-25 based) and VRC-64/GRC-160 (PRC-77 based) systems in the table but they probably are not technically part of the VRC-12 series.

All of the above radio systems make use of either the MT-1029 large Mount or the MT-1898 Mount for the R-442 receiver.

These radios came out about the same time as the PRC-77 and included provision for X-Mode operation, which at introduction was by means of the Nestor KY-8, KY-28 or KY-38 Secure Voice system, later the VINSON system  was used with the VRC-12 series radios where the KY-57 was the common Transmission Security Device.

The RT-524 or RT-246 or AM-2060() all mate with the MT-1029 Mount.

Both the RT-524 and RT-246 when used by themselves can only operate in half duplex mode, that is Push and hold to talk, release to listen.

RT-524

This radio is about the same physical size as the AM-2060 with either a PRC-25 or PRC-77 mounted.  It is a single channel radio with frequency setting using controls very similar to the PRC-25 or PRC-77.  It has a built in speaker.  The power output can be either __?__ or 30?  Watts, considerably more than the output of the PRC-25 or PRC-77 which are only a few watts.  But note this extra power only comes into play when the vehicle is sited on a hill or an external antenna like the RC-292 or OE-524 is used.

RT-246

This radio uses many of the same internal modules as the RT-524 but instead of a speaker it has push buttons for selecting one of 10 preset operating frequencies.  The physical size is the same as the RT-524.  This radio allows remote selection of the operating frequency using one or more C-2742 Remote frequency control boxes.

R-442

This is a receiver only referred to as the "auxiliary receiver".  As shown in the table above it's a part of a number of the VRC-12 Series radio systems.

Capability of the various VRC-12 Series systems

The following systems contain only a single RT: VRC-43, VRC-46, VRC-53/GRC-125 and VRC-64/GRC-160.  These systems can only be used in half duplex mode.

Systems with at least one RT and either one or two Aux receivers: VRC-12, VRC-44, VRC-45, VRC-47, VRC-48, and VRC-49 can be used in the full duplex mode which is just like a telephone where you can speak and hear the other person at the same time.  There are restrictions concerning seperation of operating frequencies and distance between antennas for this to work.  This is not to say that these systems were used that way, just that it's possible.

The VRC-48 and VRC-49 systems contain both the AM-1780 and C-2299 and are designed for retransmission opertion and need to obey the same rules about frequency and antenna seperation.

X-Mode

The X-mode connector on the VRC-12 series radios is NOT the same mechanically as the POWER connector on the PRC-77.  The jumper cap must be in place for plain text operation since it has 3 jumpers.

Pin	Function
A	X-mode in (Rx)
B	nc
C	X-Mode Out (Rx)
D	150 Hz Tone in
E	X-mode in (Tx)
F	Ground
G	X-mode out (Tx)
H	nc
J	150 Hz Tone out
K	PTT

Cap jumpers:
A to C
D to J
E to G

VRC-53 & VRC-64 Radios

Related Equipment

Manuals

The following manuals include VIC-1 onfo, but are not specific to the VIC-1 system.

VRC-12 Series & VIC-1

TM 11-5820-401-10-1

This is the operator's manual for wheeled vehicles Radio Sets: AN/VRC-12, ... AN/VRC-49 where the interphone system is typcially not used.  It does include the use of:

• RT-246
• RT-524
• R-442
• C-2742
• C-2299

TM 11-5820-401-10-1HR

This is the Hand Receipt manual for wheeled vehicles.  It's 102 pages with information on which install kits are used for which radio in which vehicle.

TM 11-5820-401-10-2

 This is the operator's manual for tracked vehicles Radio Sets: AN/VRC-12, ... AN/VRC-49 where the interphone system is typically used.  It does include the use of:

• RT-246
• RT-524
• R-442
• C-2742
• C-2299
• AM-1780 and all the above VIC-1 boxes.

TM 11-5820-401-10-2HR

This is the Hand Receipt manual for tracked vehicles.  It's 296 pages with information on which install kits are used for which radio in which vehicle.

TM 5820-401-20-1

Is the organizational Maintenance Manual for wheeled vehicles.  384 pages with lots of details.

TM 5820-401-20-2

Is the organizational Maintenance Manual for tracked vehicles.  637 pages with lots of details. 
Para 1-26 & 1-27 have a lot of VIC-1 theory

TM 5820-401-34-2-1 & TM 5820-401-34-2-2

Are the Direct Support & General Support Maintenance Manuals for the RT-246() and the RT-524() Radios

TM 5820-401-34-2-3

Is the Direct Support & General Support Maintenance Manual for the R-422()

TM 5820-401-35-1

Is the Direct Support, Gen Support & Depot Maint Manual for the C-2742 10 channel remote frequency control of the RT-246 and the C-2299 Retransmission box.

TM 11-5820-401-35-7  Control, Intercommunication Set, C-2297/VRC
TM 11-5820-401-35-9 Mountings MT-1029 & MT-1898

TC 11-4 Handbook for AN/VRC-12 Series of Radio Sets - April 1977 Training Circular includes use of VIC-1 Boxes

VRC-53/GRC-125, VRC-64/GRC-160 Manuals

TM 5820-498-12  Chapter 6 has some VIC-1 equipment info.

VIC-1 Specific

TM 11-5830-340-12 Intercommunication Set, AN/VIC-1(V) and Control, Intercommunication Set, C-10456/VRC
TM 11-5830-340-23P Intercommunication Set AN/VIC-1(V)
TM 11-5830-340-30 Intercommunication Set AN/VIC-1(V)
TM 11-5820-898-20P Amplifiers Audio Frequency AM-1780A & AM-1780B
TM 11-5895-1548-34 Audio Frequency Amplifier AM-1780B/VRC (NSN 5895-01-284-3057)
TM 11-5895-1548-24P Amplifier, Audio Frequency AM-1780B/VRC (NSN 5895-01-284-3057)
TB 11-5820-890-20-44 Installation Kit, electronic Equipment MK-2382/VRC (NSN 5895-01-330-5580) (EIC: N/A) to Permit Utilization of  the AM-1780/VRC in U.S. Army in Conjunction with MK-2347/VRC (AN/VRC-89/91/92 SERIES) 

VIC-1 realted Install Kits

TB 11-5820-890-20-44 - Mk-2382 Army Watercraft with VRC-89/91/92 SINCGARS radios
TM 11-2300-361-15-4 - VRC-12, -46, -47, -53, & GRC-125 in M60 Tank w/ 105mm Gun
TM 11-2300-364-15-1 - VRC-46, -53, & GRC-125 in M48A2 based Bridge launcher