(a) The ECM Mark 2 should be installed in the Type 8 Safe Locker. The regular location for the installation of the ECM Mark 2 is in the Code Room. Where there is no Code Room on the ship or station, the ECM shall be located where it will be protected from the weather, high humidity, excessive ranges of temperatures and espionage. The location should be suitable for regular operation of the ECM by enlisted personnel of the Coding Board and under sufficient surveillance to prevent theft or tampering. Observation of the ECM in operation should be a minimum compatible with the above requirements. The Chart House, Ward Room passageway or Radio Room would probably be suitable locations, while the Ward Room or Captain's Cabin probably would not be. In choosing the location, it should be noted that the ECM and the Cipher Unit (exclusive of Code Wheels) are classified CONFIDENTIAL, but the Key Lists, Code Wheels, etc. are classified SECRET.

(b) In a temporary installation, the wooden box in which the ECM Mark 2 is shipped may be provided with hinges and a good padlock for temporary stowage.

(c) Aboard ship, the ECM Mark 2 must be securely fastened, in both the operating and stowage positions to insure that under no conditions will it be liable to injury due to motion of the ship. Quarter-inch, 20 thread bolt-holes are provided in the base of the machine for securing it in place.

(d) The Type 8 Safe Locker can be considered suitable stowage except at shore stations where it may be unobserved for long periods of time. Due to its special design, the Type 8 Safe Locker cannot be considered as secure as standard safes which are normally provided for the stowage of classified publications.


(a) The Type 8 Safe Locker (BuShips No. 434, 703) is designed for the permanent installation of the ECM Mark 2. The Type 8 Safe Locker should be procured by all activities holding the ECM Mark 2. Class 4 and above activities having Coding Rooms in which a continuous 24 hour watch is maintained, may or may not use the Type 8 Safe Locker at discretion.

(b) The Type 8 Safe Locker is procured by request (letter, not requisition) direct to the Navy Yard, Norfolk. It is not listed in standard stock catalogs. It is Title "A" equipment and is priced at $90.00. When possible, procurement should be accomplished before actual receipt of the ECM Mark 2.

(c) The Type 8 Safe Locker is 18-7/8 inches wide, 14-1/4 inches deep and 45 inches high and weighs 172 pounds when empty. The upper door, when opened, extends out approximately 12 inches. The lower door is hinged about 2 inches above the base and, when opened, extends about 22 inches out from the front of the Locker.

(d) A lamp receptacle is provided in the upper compartment. Not less than a 25 watt lamp should be used, and it should be kept lighted at all times in order to keep the compartment free from moisture.

(e) Approximately ten feet of rubber covered cord is supplied with each Type 8 Safe Locker for connection to the ship's power supply. No terminal fitting is provided.

(f) Four 1/4" holes are prodded in the front door. The holes are properly spaced to fit the 1/4 inch bolt-holes which are provided in the base of the ECM.



Photo of Army safe with ECM installed.

(a) The Army Field Safe CH 76 is a semi-portable Field Safe designed for installation of the ECM. A limited number of these safes are available for use by naval holders at advanced bases. When used in the CH 76 Field Safe, the ECM must be installed in the special wooden box with which each safe is equipped. It is to be used by the U.S. Navy only under special circumstances, such as when the ECM is utilized ashore.

(b) The Field Safe CH-76 consists of two sections which are readily separated to facilitate carrying. Four handles are provided on each section. Each section weighs approximately 255 pounds when empty and is 31 inches long, 20-3/4 inches wide and 22 inches high. The ECM and the special wooden box weigh approximately 140 pounds, making a total weight, when completely assembled of approximately 650 pounds. Provision is made for holding two M-1 Thermite Bombs in position, ready for instant use. +

(c) Field Safes CH-76 are procured by request direct to the Commander of the Fleet under which operating.


(a) The ECM Mark 2 Is normally shipped in a specially designed packing case. This case is then "floated" in excelsior in an outer box. The outer case may have been removed prior to delivery to the ultimate holder. Specific instructions for uncrating the ECM are given on the outside of each case as follows:

(1) Set the Packing box on a bench in an upright position. The bottom of the box is the face containing four hexagon cap screws.

(2) Remove fourteen brass screws from the lower edges of the box, thereby detaching it from the wooden base.

(3) Lift the upper part of the box off the wooden base, taking care to lift vertically to avoid striking the machine.

(4) Remove four hexagon cap screws from the underside of the wooden base, after which the machine can be removed.

(5) Remove the twine holding the tape retainer and the power cord. Remove two wooden strips from between the base plate and the base casting.

(b) The special case should be preserved for future use. The ECM Mark 2 shall never be shipped or transferred without being properly crated.


(c) On receipt of the Spare Parts Box, ENG 109, the spare parts should be checked against the "Check-off List", inspected, and if desired, re-packed.


(a) When the ECM Mark 2 Is first uncrated it shall be immediately inspected for any damage that might have been caused in transportation. If damaged in shipment, a report shall immediately be made to the activity from which received. If the machine is damaged to the point where operation is not possible, the machine shall be transferred to the nearest ECM Repair Facility for repair. (See para. 501.)


(a) To inspect the machine:

(1) Remove the lid by lifting straight up.

(2) Check the register number of the Cipher Unit and the machine against the transfer receipt.

(3) Pull out the power cord and remove the paper covering.

(4) Check the positions of the indicator plug and motor plug. For 110 volt operation they should be in the positions shown in Plate 8(b), with the pointer of the shorting plug pointing to 105-125. Check the marking of the motor plug, it must be AC for 110 volts alternating current (50 to 60 cycles) and DC for direct current.

(5) Unscrew the fuse-holder caps and inspect the fuses. Five ampere fuses are ordinarily furnished, although some machines are equipped with 10 ampere fuses. (Spare fuses are in the Spare Parts Box.)

(6) Check the pawl of the hand drive lever (See Plate 8(b)) to insure that the pawl rides in the channel ring.

(7) Thread the paper tape. (See para. 406(c).)

(8) Turn to Part III and follow instructions relative to operation.


(a) Two sets of Code Wheels are normally issued with each ECM Mark 2, one for World Wide Crypto-Channels and the other for Area channels. Each holder is allowed a spare Cipher Unit (CSP 887). Spare Motors, spare Printers, Tender Repair Parts Kits, Repair and Maintenance Instructions and Blue Prints are issued only to ECM Repair Facilities.

(b) The following tabulation shows short tiles, long titles and classifications of various units of the ECM.

CSP 888 Electric Cipher Machine Mark 2 (without receptacles for parallel operation.) Confidential
CSP 889 Electric Cipher Machine Mark 2 (with receptacles for parallel operation). Confidential
CSP 887 Cipher Unit (Including Index Wheels). Confidential
CSP (var) Code Wheel Sets (Each set normally consists of ten Code Wheels). Secret
CSP (var) Key Lists Secret

ENG 106 115 volt, alternating current (50 to 60 cycles) Motor. Unclassified
ENG 107 115 volt, direct current, Motor Unclassified
ENG 108 Printer Unclassified
ENG 109 Spare Parts Box Unclassified
ENG 110 Tender Repair Parts Kit Unclassified
ENG 111 Connecting Cable (for parallel operation). Unclassified
ENG 112 Place Finder (discontinued, no longer available). Unclassified
ENG 130 24 volt, direct current Motor Unclassified
ENG 131 12 volt, direct current, Motor Unclassified


(a) RPS-4(A), paragraph 501, states:

(1) Stowage of SECRET and CONFIDENTIAL registered publications:

(A) Secret and Confidential registered publications will be stowed in the most secure space available, preferably a three-combination safe or vault. If a three-combination safe or vault is not available, then the publications should be kept constantly under armed guard.

(2) Stowage of non-registered publications:

(A) Secret and Confidential non-registered publications will be stowed in the most secure files available in a room that is kept locked when not in use.

(B) Restricted publications will be stowed and handled in such a manner as to insure a reasonable degree of security.


(a) In accordance with the regulations set forth in the current edition of the Registered Publication Manual, (RPS-4), CSP's 888/889 and associated publications will, while being transported, invariably be accompanied by a commissioned officer.


(a) RPS-4(A), paragraph 512 states:

(1) The importance of maintaining the contents of registered publications and devices "Secret" or "Confidential" as indicated on the publications cannot be too strongly emphasized. Should a Secret or Confidential publication or device be lost or compromised the fact shall be reported direct to the CNO immediately by dispatch, with the fleet, force, or shore based commander as an information addressee. Following this report, the commanding officer of the ship or station to whom the lost or compromised publication or device is charged shall conduct a thorough investigation in accordance with Article [76(7)] U.S. Navy Regulations, and he shall indicate in his report the action taken or recommended. The report of the investigation shall be forwarded to the CNO via the chain of command. In the case of Secret or Confidential publications or devices lost under circumstances which preclude the possibility of compromise, as by accidental burning or actual sinking in deep water, the direct immediate report is not required. The initial report in this case shall include the report of the investigation conducted by the commanding officer and shall be forwarded via the chain of command. In either case, the report of the investigation shall be submitted to the CNO ( ------ [Art. 76(7)(c)] ------, U.S. Navy Regs.) Upon receipt of a loss report by the CNO, if appropriate action has been taken by responsible commanders, the publication(s) lost will be removed from charge.

(b) Any circumstances, such as safes being insecure, or having been left unlocked, or Secret or Confidential publications and devices having been left unguarded, which may in any way involve the compromise of such matter, shall be promptly reported to the CNO.




(a) Emergency destruction of the ECM and associated publications carried afloat is most readily accomplished by throwing them overboard in deep water. The water must be deep enough to insure that the machine and publications cannot be salvaged. Ashore, or in shallow water, the ECM and associated publications should be destroyed as described below.


(a) Destruction of electric cipher machine systems should be accomplished in the following order:

(1) Code Wheels

(2) Key Lists

(3) Machines


(a) Code Wheels should be destroyed in the order of greatest number distributed. (Class 3 World Wide, Class 3 Area, Class 4, etc.) Reserve-on-Board Code Wheels should be destroyed before effective Code Wheels.

(b) The wiring should be destroyed first:

(1) With a small torch unsolder the wires, and with a long nose pliers remove the wires from the Code Wheel. Cut the wires into small pieces and dispose of the pieces in any manner possible, compatible with circumstances and facilities available, which will prevent recovery.

(2) If a torch is not available, cut the wires as close as possible to the solder lug or pull the wires off. Dispose of the wires.

(c) In the case of the CCM Code Wheels, it is also extremely important to destroy the Code Wheels themselves, as well as the wiring, since the Code Wheels contain cam-contours.

(1) With a heavy hammer smash the Code Wheel faces into bits and dispose of the pieces to prevent recovery.

(d) If limitations of time or conditions of silence exist wherein the Code Wheels cannot be destroyed they should be disposed of in any manner possible which will at least delay recovery. If thrown overboard, they should be thrown singly in different directions.


(a) Key Lists should be destroyed in the order of greatest distribution (Class 3 World Wide, Class 3 Area, Class 4, etc.). Reserve-on-Board Key Lists should be destroyed before effective Key Lists.

(b) The preferred method of destruction is by burning, but care must be exercised to insure that every piece is burned and the ashes completely broken up to prevent reconstruction. Some Key Lists are printed on specially coated paper from which the printing will loosen upon immersion in water. This is an emergency provision only and such Key Lists should nevertheless be burned if time permits.

(c) If sufficient time is not available for burning, Key Lists should be thrown overboard in a perforated weighted bag.


(d) Key Lists that cannot be burned or thrown overboard in a perforated weighted bag should at least be torn into bits and the pieces scattered.


(a) The most important cryptographic part of the ECM is the Cipher Unit and wiring which leads to it. The Zeroizer is next in importance, with the balance of the machine and wiring last.

(b) To destroy the ECM proceed in the following order:

(1) Remove the Cipher Unit from the machine, withdraw the Index Maze Spindle and remove the Index Wheels. Destroy the Index Wheels by smashing them with a heavy hammer. Cut the wires into pieces. Dispose of all parts in accordance with facilities available. Leave the Cipher Unit frame for destruction with individual parts of the machine.

(2) Remove the cover of the machine. (Two screws are located in front, one on each side, and one screw is located in the rear (inside)). Remove the protective plates on the left and right sides of the cipher unit frame. At this point time available determines the procedure.

(A) Unsolder all connections or cut the wires as close to the soldering lugs as possible.

(B) Cut the cables leading to the distributor plates as "straight across" as possible. (This is to prevent reconstruction by means of the color coding of the wires and may be omitted if time is sufficient to burn the entire machine.)

(C) Cut off the cable to the Zeroizer at the base and remove all wires from the Zeroizer.

(D) Destroy the ends of the cables thus cut, in any manner possible.

(3) With the Code Wheels and Key Lists destroyed and the Machine prepared as in the foregoing paragraphs, the main cryptographic features are destroyed - the rest of the machine (motor, printer, controller, keyboard, etc.) are items such as any Cipher Machine might contain. To make destruction complete smash all units (including the separators of the Cipher Unit) to destroy their usefulness. Cover with inflammable material and burn. Special attention should be taken to insure that the color coding of the wires is burned off and the wires broken.

(4) Dispose of all parts as best possible to preclude any recovery.


(a) Demolition charges may be used for the destruction of the machine but should not be depended upon to destroy the Code Wheels. If it is intended to use a demolition charge for the destruction, the following items should be prepared as a destruction kit:

(1) 2 one-half lb. standard TNT demolition charges.

(2) 2 detonators for above, for electric firing.

(3) 2 detonators for above, lighted fuse type.

(4) 2 four-foot length, standard fuses (42 ft/mm.).

(5) 1 exploder device with necessary wire for rigging.

(6) Tools: Heavy hammer or axe; knife suitable for installing demolition charge, cutting wire, etc.; heavy metal plate, block or rock suitable for use in smashing Code Wheels with a hammer.

(b) One destruction kit should be provided for each machine and maintained for instant use. Exploders should be installed at a fixed remote location accessible for immediate use and wired to the location of machines. Detonators shall be stowed in destruction kit but shall be located in a safe place easily accessible to operating personnel.


(c) To destroy the machine, remove CSP 887 (Cipher Unit) and install demolition charges In front left-hand corner of the cavity normally occupied by the Cipher Unit. Install the detonator and wiring or the fuse. Be sure that all personnel are clear before final connection of exploder is made or fuse Is lighted.


(a) The M-1 Thermite Bomb is designed for emergency destruction of the ECM. Each bomb is packed in an individual container which weighs approximately 55 pounds. The container is 24 inches long, 20 Inches wide and 3-1/2 inches high.

(b) The M-1 Thermite Bombs are standard items in the U.S. Army as well as the U.S. Navy and carry the same designation in both services. They may be procured from Naval Ammunition Depots at certain locations, by request to the Fleet Commander who has directed distribution.

(c) To unpack the M-1 Bomb, remove one side of the wooden container. Remove the mounting brackets and mounting screws. Cut the moisture-proof paper wrapping and lift out the bomb.

CAUTION: In unpacking the bomb, care must be exercised that the bomb is not detonated by the accidental releasing of the firing ring of the manual detonator.

(d) Tape the firing ring of the manual detonator against the detonator.

(e) To prepare the ECM for destruction with the M-1 Thermite Bomb:

(1) Remove all Code Wheels from the ECM. Insert the Cipher Unit; the Index Wheels may remain In the Cipher Unit.

(2) Do not replace the lid.

(3) Place the Code Wheels on top of the machine in such a manner that they lie flat and as near the center of the machine as possible, but do not pile the Code Wheels on top of one another. Only one set of Code Wheels should be destroyed with the machine, but in case of emergency, Code Wheels may be piled one on top of another to a depth of three.

(4) Place the M-1 Bomb on top of the Code Wheels with approximately the same length of the bomb extending over each end of the machine.

(5) Detonate the bomb, either electrically or manually.

(f) To detonate the M-1 Bomb, electrically:

(1) Uncoil the wires, and twist together the bare ends of ONE wire from each pair of wires.

(2) Twist together, the bare ends of the other wires from each pair of wires.

(3) Stand to the side of the M-1 Bomb and touch the twisted ends to a source of voltage.

NOTE: Any voltage from a 1-1/2 volt flashlight up to a standard 110 volt lighting circuit may be used.

(g) To detonate the M-1 Bomb manually:

(1) Remove the tape holding the firing rings of the manual detonator in place.

(2) Stand to one side of the M-1 Bomb and pull the firing ring of the bomb.

(h) The M-l Bomb does not explode, and a few seconds will elapse from the time the bomb is detonated until it is dangerous. If several bombs are to be detonated manually, start on one end and pull the firing rings in sequence.


(i) Approximately two minutes are required for the bomb to "spend itself", but the machine will be left burning furiously.

(j) The M-1 Bomb is not recommended for destroying publications due to the difficulty in burning stacked sheets. Publications should be torn apart and each sheet crumpled before subjecting to fire.



(a) Sets of Code Wheels which have been superseded and which have been specifically ordered returned in accordance with this paragraph (or CSPM 374) should be prepared as followed:

(1) Cut or unsolder the wires from the solder lugs of all Code Wheels, being careful not to damage the Code Wheels or the solder-lugs. Destroy the wires or dispose of the pieces in accordance with facilities available.

(2) Remove the nameplate containing the CSP number and Register Number from the Code Wheel box, and place it in the box with the unwired Code Wheels. Suitably tag the box "RESTRICTED".

(3) Submit the usual Destruction Report.

(4) Transfer the Code Wheels to the nearest Issuing Office.

(b) Issuing Offices forwarded by ordinary mall or express to:

The Naval Code and Signal Laboratory
Communications Annex
Washington, 25, D.C.

(c) If facilities are available (such as ECM Repair Facility) Issuing Offices should prepare Code Wheels remaining in stock, as directed above; otherwise the Code Wheels must be returned by Officer Messenger.


(a) Whenever a ship or station is unable to use the ECM Mark 2 for its classified communication, because the machine is inoperative or because essential elements are lacking, that fact should be reported to the Chief of Naval Operations and to other superiors in the chain of command, as soon as practicable. The ship or station should also report when the ECM Mark 2 is again in operating condition. These reports need not be made by vessels having more than one ECM unless all are inoperative.

NOTE: This shall not be construed as authorizing violation of any condition of radio silence which may have been imposed by competent authority.

(b) The following guarantee is part of the contracts under which these machines were purchased:

"Contractor shall guarantee satisfactory performance for a period of one (1) year provided that such period shall not extend longer than two (2) years from date of delivery to the Navy. This guarantee shall include guarantee of all parts against defective design, material, or workmanship, and contractor shall agree to replace with satisfactory material any part found defective within the guarantee period, without cost to the Government."

In order to take advantage of this guarantee as well as to be informed of defective design or material as early as possible, it is essential that any defects be promptly reported on Bureau of Ships form NBS 383 by the activity effecting the repairs (normally an authorized ECM Repair Facility). The three white copies of NBS 383 should be sent to the Inspector of Naval Material, Chicago, Ill.; the yellow, green, and blue copies should be sent to the Bureau of Ships; and the salmon copy retained by the reporting activity. These reports should be marked "CONFIDENTIAL".



(a) In writing these operating Instructions, an attempt has been made to make them as simple and as brief as possible. Information that is obvious has been omitted. Pictures and labels have been substituted for descriptions where practicable. The Parts List (with tracings, names, and part numbers) will be found in the Repair Instructions, furnished only to ECM Repair Faculties. Information necessary to the operation of the machine and not readily available to the holder has been included, insofar as service needs could be anticipated.

121. CRITICISMS OF ECM PUBLICATIONS. (a) It is requested that any comments, criticisms and suggestions in regard to these Operating Instructions, the Repair Instructions, or the various Key Lists be submitted to the Chief of Naval Operations. Such comments should be specific as to publication, page (or paragraph) and subject matter. It is particularly important that any instructions that are not clear, too brief, or apparently lacking, be reported without delay in order that they may be incorporated in the superseding edition.


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