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PLUG, DUMMY, WE 165. Used for holding circuit open in pin jack boards. Wooden plug, 2" long, with shank formed like single conductor plug.
PLUG, SPLIT, 2-A. Used in peg switchboards to loop in a portable Morse set. Tapered brass rod separated into equal halves by insulation with screw terminals and hollow fiber handle. 3" long by 3/4" wide.
PLUG, TWIN, 1-A. Used to connect portable Morse or other sets to Weatherproof Loop Jack 1-A. Two double conductor plugs (with special shells) set in a brass shell shaped like a flattened tube. L--3 3/4", W--1 ", T--3/4".
POLECHANGER, GRAVITY BATTERY.  [Refer all needs to Vice Pres. Plant] Used on duplex or quadruplex sets operated with gravity main battery.  A Morse sounder with armature extended in opposite direction from anvil to move a contact set between two small contact levers. Form a "continuity" type polechanger (short circuits battery momentarily).  L--9 1/4", W--4 3/4, Ht--4 1/8".
RECORDER, SIPHON .... DISTANCE. Used as a recording instrument in ocean cable service. A group of permanent and electromagnets which operate a siphon tube set on a sensitive suspension. Motor in base feeds paper from reel in base. SHORT distance type suitable for cables up to 500 miles in length. LONG distance type is more sensitive because of larger coils and stronger fields. Approximate size 15" x 15" x 18" high.
REGISTER, DOUBLE PEN, .... [Give resistance for 1-C type.

Used on messenger call circuits to register calls. A clock work mechanism which is started by movement of the armature of an electromagnet connected into the register leg of the call circuit. Starting of the mechanism draws paper tape through between a thin roller and a "pen" which throws tape against roller when armature operates. Edge of roller is inked by an ink wheel and makes mark on tape each time pen operates. Has two pens and two electromagnets, thus caring for two circuits. Clockwork is in metal case with subbase, coils and pens being on outside. Tape is carried on a bracket arm.

Type Resistance Current Where used
1-C 6 250  26 and 52 volt old style board
1-C 400  50 All voltages, #2 type units.
3-A 3000* 30  With #3 type units.

* Resistance of coils is 1000 ohms, balance being added resistance mounted under base. Supersedes 2-A 1900 ohm register, which had 400 ohm coils with 1500 ohms added.

 L--10 ", W--7 1/4", Ht--6".

RELAY, BOX. Formerly used where main line sounders are now used. Ordinary Morse relay with all or part of coils surrounded by wood box to increase volume of sound. Had key on base giving rise to "K O B" designation for portable set.

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Used as a line relay on front locking shunt contact repeaters. Generally similar to a Morse relay but armature is taller in order to enter field of a single coil locking magnet mounted above the main line magnets. Has slate base mounted on iron subbase. Resistance of holding coil must be specified. This is 12 ohms for primary battery locals and 80 ohms for all other voltages. Main line coil--150 ohms 40 mils; holding coil 12 ohms 250 mils or 80 ohms 110 mils. L--8 1/4"; W--4 3/4"; Ht--4 ".
RELAY, LOCKING, 3-A.  [Will be furnished interchangeably with 2-A type]  A neutral relay 7-C rewound to operate in the same circuits as locking relay 2-A. Currents required are identical. Main line coil--270 ohms; holding coil--5 and 45 ohms respec. (The holding coil has two spools instead of one as on the 2-A relay.)
RELAY, MORSE, ...., .... OHM.  rly4d.jpg (34939 bytes)

For general use in single Morse operation. Common telegraph relay with pair of adjustable magnets, armature, "goose-neck" contact carrier, all mounted on a wood base. Type 4-B, the oldest model is mechanically larger than the later 4-C and 4-D, and has a higher resistance for a given operating current. The 4-B type was originally made in 35 and 150 ohm resistance, but 150 ohm only is now furnished, the other being superseded by 4-C 25 ohms. The 4-B type must be used wherever space and resistance will permit.

Type Resistance Normal  Current   L   W   Ht
4-B 150 40 8 1/8" 4 3/4"  3 "
4-D*  25 60 7 3/16" 3 7/8"  3 3/4"
4-D*  100 40                same
   *4-C is practically identical and interchangeable.

[Close-up of Relay 4-D label]


Used on circuits such as quadruplex, central battery duplex, etc., which require a differential non-polar relay. Also used on simplex telephone circuits per Specn. 559. Two pairs of electromagnets, the larger, or main line pair being set side by side, and the upper or holding, pair set one above the other. The line coils are each wound differential, while the holding coils are single wound. A single armature is mounted in the field of both main line and holding coils. Slate base with iron subbase. Resistance--each line circuit approx 250 ohms; holding coil 2000 ohms. L--8 1/4", W--4 7/8", Ht--5 ".

* Older relays types 7-A and 7-B had a holding coil of only 230 ohms.

Relay, Polar 6B.rly6b.jpg (47807 bytes) [This relay is not shown in the 1929 Plant Catalog]
RELAY, POLAR, 6-C. Used as line relay on key worked duplex sets and as leak relay on various repeater circuits. Two J-shaped permanent magnets with a coil on each short leg. Each coil has two 200 ohm windings wound differential. Tubular steel armature vibrates between pole pieces. Contact carrier is set on slide blocks which can be moved by thumb screw. Has slate or fibre base set on iron subbase. L--8 1/4", W--4 3/4", Ht--2 3/4".

*Two other types of relay, the Frier and the 16-A will be furnished interchangeably as available in stock. The Frier type can be identified by the fact that coils are encased in a brass case, while the 16-A type has a single L-shaped permanent magnet.

RELAY, POLAR, 17-B.*  [See also Relay, Wheatstone]

Used on printer and other high speed circuits where relay of the 6-C type is not of sufficient speed. A U-shaped magnet with one leg bent upwards to a horizontal position to form mounting for a pair of coils set side by side with armature between them. Each coil has three windings, two main line which are differential--and a third for local circuit. Contacts are set on sliding block. Relay is fastened to a relay mounting 2-A for quick attachment to relay subbase 2-A (ordered separately), and has a cylindrical cover with hinged top in which is set a magnifying glass for viewing the contacts without opening the top. Dia--5 1/8", Ht--5 3/8".

* A few 17-A relays built on the same general principles are also in service.

RELAY, PONY. Obsolescent, formerly used on time service. Similar to Morse relay but of smaller dimensions. Resistance 20 ohms, current 130 mils.
RELAY, SINGLE-CURRENT, 10-A. Used on duplex or other sets carrying signals at speeds higher that those normally used in Morse circuits. A relay mounting 2-A in which is set a single coil relay. Coil is of form wound type and sets vertically with armature passing through it horizontally. A C-shaped laminated yoke sets at one side of coil on a moveable plate which allows adjustment of air gap between yoke armature by means of a knob and eccentric. Tension of armature retractile spring is adjusted by a similar knob through a cam and lever. Mechanism is covered by a rectangular steel case through top of which adjusting knobs protrude. Resistance 125 ohms; normal operating current-- [No value shown] Dia--5 ", Ht--4".
RELAY, TELEGRAPH, WE 26-A. Used on telephone selector message circuits to reverse polarity of line signaling battery. Much like Morse relay 4-D but has two armatures each with front and back contact. Resistance 25 ohms, current 300 to 400 mils.
RELAY, TRANSMITTING, #28 and #29 Types. Morse relays with an extra pair of contacts added in order to make them equivalent to transmitting relays for front contact shunt locking repeaters. Type 28 was constructed from a spectacle type Morse relay, the extra contacts being above the regular ones. Type #29 was constructed from Morse relays 4-C by interposing the extra contacts between the armature and contact, the extra contacts being mounted on a bracket at the side of the relay.

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Used on single line repeaters of the front locking shunt contact type. A relay either of the Morse 4-C or 4-D type, or of similar design, with an extra pair of contacts added in order to close two circuits when the relay is energized. One pair closes before the other and this pair is the last to open. Two types are furnished interchangeably, WE 24 or #30 (W. U. Specn.). Each made in two resistance values, 25 ohm or 400 ohm. #24 type is coded 24-C for 25 ohm, and 24-D for 400 ohm, while coding of the #30 is the same for either resistance. Type 30-A (Specn. 1369-A) is made by converting a Morse relay, while type 30-B (Specn. 1888-A) is a direct manufacture. All of these relays have lugs for connection of coils in series or parallel.  [30-B label.  This relay was made by Liberty Electric Co.]

Type Resistance   Current  
Series Parallel Series Parallel
25 ohm 25 6.25 110 250
400 ohm 400 100 30 60

L--7 3/8", W--3 7/8", Ht--5 3/4"                                     

RELAY, WEINY PHILLIPS.   Used as a line and locking relay in Weiny Phillips repeaters, which are obsolescent. Similar in design to a locking relay 2-A, but locking coil has a tap at middle point, making two 40 ohm coils. Locking coil is demagnetized by operating these coils differentially instead of by shunting the current out of them as is done in the front contact shunt locking repeater. For other data see Relay, Locking, 2-A.

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rly1ftp2.JPG (68849 bytes)

Used interchangeably with polar relay 17-B for operation of polar high speed telegraphic circuits. A U-shaped armature set on its side with horizontal legs bent back into a half circle within which two vertical spools are set. Each spool has from three to five windings for main and artificial lines, and local circuits. Armature consists of thin vertical spindle with field pieces at top and bottom and tongue at top. Base of relay is a relay mounting 2-A, on which is set a cylindrical composition dust cover with hinged glass cover to give access to armature and points.

Type Usage Number of windings per spool
COMB. 1-A, 1-B* 

1-C, 1-D,  1-F

 General Use 4--main, artificial, accelerating  and opposing.
 3-A, GND CORRECTOR. Relay Ground Correction 3-main, 2 auxiliary, (one on each spool)
4-A Superposed Universal Repeaters 5- 2 main, 1 artificial, accelerating and opposing

 Dia--5 ", Ht--5 1/4". 

*An older type 1-B (without the word "Combination") had only the main and artificial windings. Relay type 2-A had no permanent magnet, but was energized from a local winding.

RESONATORS. [Information only

These items are grouped here for convenience. Each item must be ordered separately, and is listed separately. 

Resonator 3-A, now obsolete, can be converted to 7-A by addition of one Resonator Extension Arm. 

Resonator 5-B is used on desks, etc. where portability is desired. 

Resonator 6-B is used on tables having flat belt equipment. Resonator 7-B is used on non-belt or V-belt tables.

Arm, Resonator Extension.  An iron arm similar to center arm of 7-B resonator. L--10". Ht--2 3/4".

Block, connecting, 7-B. Used to terminate resonator cord on duplex positions. Composition base with three 3 pairs of screw type posts and a metal "snap" cover. L--2 1/8", W--1", Ht--7/8".

Bolt, Sounder, 2-A.  A #8-32 x1 " R.H.I. machine screw, with thumb nut and washer used to fasten sounder into hood.

Cord, Resonator.  [Pieces or feet] Piece of standard #18 ga. twisted pair black lamp cord used to connect sounder in resonator to instrument on table. If ordered by "pieces" comes in 5 ft. lengths ready to use.

Hood, Resonator.  Used as sounding board for one or two sounders. Triangular wooden box of triangular vertical cross section with one side open. W--7", Ht--7 1/4", D--5".

Resonator, 5-B stand only. Iron stand similar to telephone desk stand with flat plate for mounting resonator on. Ht--8", Dia. base--5 1/4".

Resonator, 6-B, frame only. A triangular bracket for attachment to conveyor structure, two additional swivel arms, and a swivel plate for bottom of hood.

Resonator, 7-A, frame only. A triangular base with shaft at top for first swivel arm, three arms, and a swivel plate for hood. Shipping size 12" x 7" x 3".

Resonator, 7-B, frame only. Used on various Morse tables. See description above.

Resonator, 5-B, stand only.   Used where portability of resonator is desired. See description above.
Resonator, 6-B, frame only.   Used on flat belt type structures. See description above.
Resonator, 7-A, frame only.  Used on various Morse tables.  See description above.
RHEOSTAT, RADIAL ARM, #17. An older type of rheostat no longer furnished. These are much like #1 type but had one less single dial. Some #17 rheostats have wood, others steel cases. Some had no front plate, the binding posts being on top, others had binding posts on front. All those having a front plate are convertible to 1-BB type.
RHEOSTAT, RADIAL ARM, 1-C.* Used on duplexed circuits of all kinds for providing resistance in artificial line. Sheet metal box with top and one half of front of composition. Top has one double and 3 single dial switches and front face has one single switch and 5 binding posts. Type 4-A resistances connected to dials give 250 and 2500, 8250, 1000, 125 and 600 ohms resistance with intermediate taps on all. W--6 ", Ht--8 1/4", D--7 ".

*1-A type did not have "zero" stud on 600 ohm dial and some have wood case. 1-B type is almost similar to 1-C. 1-BB type is made from an older rheostat #17 type, which see. All three are interchangeable in use.

RHEOSTAT, 16-A.   Used to control bias current on telegraph sets having polar relays in operation on single current circuits. Rectangular metal case with single 12-step dial on top and 12 type 1-A resistances to give 250 ohm steps up to 9000 ohms. W--4 3/4", Ht--6 ", D--3 1/4".

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