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REF I,J2_:A2436014 

LETTER IW •. :. g2 

SPSIC 461-Codes 

(24 July 43) 

.. 

8 E G R B :E' 

WAR DEPART1'..IENT 

HEADQUARTERS 7 ARJ:~Y SERVICE FORCES 

Office of the Chief Signal Officer 

Washington 25, D.C. 

SPSIC-4 

1 .August 43 

: SUBJECT: Issue of 131-A-l and I\':-228 Equipment. 

TO: . 

• ? •• 

.. 

OEORB'.f' 

By authority of the 

CHIEF SIGNAL OFFICER rnitia18~--~--nate 

.--··· -: / , ... · ,,,.,. 

. _.,;:""' ________ -·· /·,,.-.·/?';"< _:_:::_:.!..,_:_·:>: 

1. The· War Department has fl.Uthorized the dis:cussion of the · te ch.nical aspects· of the 131-.A-l applique unit using double transmitter distri.butors with interested British services. 

2. · The: l31-A-l applique unit for use vvi th enc.iphering tapes 

may be ihstalle~:in British headquarters for use in liaison with 

United States Army headquarters. This equipment may be ,qperated by the British. 

3. The follov-Jing policy should be used as a guide in the 

issue and use of the equipment~ 

a. The 131-.A-l eauipm.ent with double transmitter distributors Ylill pe used for c~mb1ned communication QlLYt.ir.§._Ci.£.£.Jdi ts 

.QD1:Z· It ·is ~ot c-ontemplated that this equipment will be used for 

combined rad:io!. :t;::omnv_picationo . . ;. ~· • . . i - • ; .. . 

b. The. 131-A-l equipment nill be United States owned 

and installed. The equipment may be installed on wire lines under 

British or combined control, the maintenan_ce of the lines and 

switching equipment to be British or cowbined as the case may be. 

It is realized that it will be necessary for British line maintenance personnel to test through the 131-A-l equipment on British 

controlled lines in performance of their duties, however, .QJJ.1Y 

§Q.ih2.r:iz.Qsl.J2.§.1:..§..Qllll.§.1_Ei 1Lhia.ng1 e -thQ __ Q1£.§.§if.iQf!_.i.fil2.§..§. • The 131-

A - l equipment itself will be maintained by United States Army personnel. 

c. All systems including tapes and key lists will be 

prepared by the Chief Signal Officer, United States .Army, Different systems, including tapes and key lists, will be prepared for 

each separate net. 

d. The classification of the traffic handled will be 

limited to United States RESTRICTED and CONFIDENTIAL; British CONFIDENTIAL and SECRET. 

s E . 0, R. E '±' .·· ,, . 

Declassified and approved for release by NSA on 09-20-2013 pursuantto E .0. 1352a 
REF.AD:A2436014 

SPSIC 461 Codes 

• 0 E3 G R E T • 1 .August Ll-3 

Subject: Issue of 131-A-'l ·and 11·~-228 ·Equipment 

4. The ~ar Deprirtment has ~uthorized the issue of the Converter M-22G to be used on.land lines under British or combined 

c on tr o 1. .±hg_Q2nY.~.r.t.SlJL.:.M-2·2 q ·wi11_n21_P:L2h owri_12~_g i s__g_:g,22 e c!_l!i.th.:L. 

llQL .. .Ql2SJ.t a t §.g_J2y__§.r\Y..Qll2-21h ~.r_!ha g __ s.!d:t..h.9. r t.~.~g_12gr.§..Qrill:QL.QL1b& 

_____ 

Arn.ad Forces of the United States. _.. __ ~-~-""".,.----·------------.-. 

· ·5:~ -Th~·'ro1iouing ~olicy should be used as a guide in the 

issue and use of the M-228 on land-line circuits under British or 

combined contr~l-·-

.. . a. The termina.l equipment must be under exclusive 

: United. $tates mili t0rY con .. i:;rol •. United ·states Army personnel will 

install. and m0in.tain the Cortvert13r ·M-2~8 .and associated equipment 

as well as the ·wire ·circuit as far as the outside of the c·ode room. 

. . b~ Te:rrniJ;lal and.- swi tchlng ·equipment throut;h which land1ine circuits pass< e:·arrying J.I..:.228 'traffic, must be under United 

Siates Army supervision. 

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For the Chief Signal Officer: 

.. II ( , -......__ ~-;-:£·~- ~'\ 

. --~::_/--··' -.,+ .... '1 ., . -·- .,_ ___ .. -. .__,, . ·--· ('._.'(_ .• _-'1,., • ....-:t 

· · S. P. Collins 

Colonel, Signal Corps 

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