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Racal MA-4450 (MEROD)
Message Entry and Read-Out Device

The MA-4450 was a Message Entry and Read-Out Device (MEROD) developed by Racal COMSEC in Salisbury (UK). It was intended for sending encrypted messages in burst mode over a radio link, and was therefore often used by Special Forces (SF) in combination with a manpack radio.

The image on the right shows a typical MA-4450 with the optional illumination lid opened. It has a large LCD screen at the top and a keyboard with 51 rubber keys below it. The keyboard consists of the usual alphanumerical keys (0-9 and A-Z) with the common QWERTY layout. At the top row are 7 function keys, the rightmost of which is the OFF key. At the bottom are the space bar and two large keys for left and right.

The MA-4450 is also known as a Tactical Data-Entry Device (TDED) or by its National Stock Number (NSN) 5811-99-722-5579.
Operating the MA-4450

All connections are at the rear of the unit. There are 4 sockets for RADIO, HANDSET, PRINTER and a REMOTE port. Each socket accepts a different type of connector, so that mistakes are avoided. Power is supplied to the MA-4450 via the REM-PORT. When the optional illumination lid is fitted, it takes its power from the PRINTER socket, to which it is connected by means of a short lead.

For use in the field, and in particular by special forces, the MEROD would generally be packed inside a nylon 'raincoat' or carrying pouch, such as the one shown in the image on the right. It allows the device to be carried at the shoulder or to be attached to the webbing. The MEROD can be operated from within the pouch that has various pockets for the ancillaries, cables and the junction box. Further images below.

A small junction box is used to connect the device (TDED) to the radio and a suitable DC power source. This junction box is known as the Rapier Interface Box (RIB). It has the designator MA-4271 and can be installed in one of the pockets of the pouch.

A special version of the MEROD was made for the US Special Forces. It is designated KY-879/P and has NSN 5820-001-100-3194.
MEROD MA-4450 in carrying pouch, with lid open

MA-4450 in carrying pouch MA-4450 with closed lighting panel (lid) MA-4450 ready for use Operating the MA-4450 Junction box The junction box inside the carrying pouch Junction box with cables MA-4450 ready for use MEROD MA-4450 in carrying pouch
MEROD in nylon carrying pouch Closing the velcro edges of the carrying pouch MA-4450 rear view MA-4450 rear view with lighting panel connected Front view of MA-4450 MEROD unit with open lid Frontal view of a MEROD unit Close-up of an LED in the optional illumination lid

Dutch Special Forces
During the 1980s MEROD devices, such as the MA-4450, were used by Dutch Special Forces (104 Waarnemings- en Verkenningscompagnie) for operations behind enemy lines, in many cases combined with a manpack radio set, such as the AEG Telefunken SE-6861 (Dutch: LAPR).

The image on the right [2] shows Dutch Special Forces (Commando's) using a MEROD device in an underground hideout. At the top right is the SE-6861 radio set. In the Netherlands this radio was commonly known as LAPR which is short for Lange Afstands Ploeg Radio (Long Distance Group Radio) or by designator KL/TRC-5151.

The MEROD itself was known in The Netherlands as Digitaal Berichten Apparaat or DBA (Digital Message Device). It was also used at the other end of the link, e.g. in the (mobile) command center shown in the second image below [2].
Dutch Special Forces using MEROD in the field

MEROD was also used in combination with the MA-4420 MEROD base station, which allowed messages to be (pre)recorded, stored and printed. It could also be controlled by a computer.

Dutch Special Forces using MEROD in the field Dutch special forces using MEROD in a command center Racal MA-4420 MEROD Base Station

Below is an overview of the various parts that are used in combination with the MEROD. The first section of the table lists the parts and cables that were supplied with our MEROD. The lower section shows the cables that are listed in the manual. If you know of any other ancillaries, please let us know.

Name Description Designator NSN  
MEROD Message entry device MA 4450 5811-99-722-5579  
RIB Rapier Interface Box MA 4271 5811-99-786-8876  
BCPP 2m cable 7-pin male to 50 pin Centronics BA 453840 5811-99-786-8879  
HANDSET 10 cm cable 7-pin male to 7-pin female BA 454625 -  
TDED 30 cm cable 7-pin male to 7-pin male BA 453848 5811-99-786-8886  
DC SUPPLY Cable 4-pin female to 3-pin male BA 453844 5811-99-786-8882  
RADIO Cable 7-pin male to 7-pin male BA 454624 -  

The following cables are listed in the manual:
BCPP 2m RIB SKA to Computer BA 453840 5811-99-786-8879  
RADIO 2m TDED SKD to CNR or CUR BA 453841 -  
RADIO 6m TDED SKD to CNR BA 453842 -  
DC SUPPLY 2m RIB PLG (PSU input) to PSU BA 453844 5811-99-786-8882  
DC SUPPLY 6m RIB PLG (same as above) BA 453845 -  
DC SUPPLY 1m RIB PLG to vehicle battery BA 453846 -  
DC SUPPLY Y-cable 453844 to CUR heated-glove socket BA 453847 -  
TDED 40cm RIB SKL to TDED REM-PORT BA 453848 5811-99-786-8886  
DC SUPPLY 1m RIB PLG to EDED Standby Pack BA 453856 -  

BCPP   Battery Command Post Processor
Tactical planning, deployment and management computer system.

CNR   Clansman Radio
The MA-4450 MEROD was initially designed for use with the British Clansman series of military radios. With an appropriate adapter cable it can also be used with other radios.

CUR   Communications Unit Rapier

RIB   Rapier Interface Box
A small junction box (MA-4271) that is connected to the REM-PORT (Remote Port) of the of the MEROD. It has two sockets (TDED and BCPP) that are connected in parallel and a smaller PSU socket. It allows the MEROD to be connected to a power source and a computer/peripheral simultaneously.

TDED   Tactical Data-Entry Device
The is the actual MEROD or MA-4450 device.

PSU   Power Supply Unit (e.g. vehicle battery)
External power source for the TDED, which can be a CUR, a branch cable (Y-cable), vehicle battery, external PSU or TDED Standby Pack.

The diagram below shows how the various parts are connected via the supplied cables. Basically, the MEROD is connected in between the radio and the handset. A short optional extension cable of approx. 10 - 20 cm (BA 454625) may be used for easier connection of the handset, whilst a long cable (BA 454624) connects the MA-4450 to the radio. If the optional illuminated top lid is present, it should be connected to the PRINTER socket (SKB) of the MEROD as shown here:

The Rapier Interface Box (RIB) is connected to the Remote Port (REM-PORT) of the MEROD. It bascially expands the REM-PORT into two identical ports (TDED and BCPP) and allowed an external power source to be connected simultaneously to the DC SUPPLY socket at the right.

  1. Racal, MA-4450 Operators Handbook
    Tactical Data-Entry Device (TDED) MA 4450 Version 1.
    TH 8426, Issue 1, April 1987.

  2. Anonymous source, Images of Dutch Special Forces using MEROD
    Photographs reproduced here with permission from the owner. March 2012.

  3. Racal-Comsec, MEROD - Message Entry and Read Out Device
    4-page full-colour brochure of the MEROD terminal. Date unknown.
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