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(b) Aeroscopes serial number of each instrument.

(c) Telephones-names of manufacturer and serial numbers, com

posite type, common battery, or service telephones.

(d) Telephone switchboards-name of manufacturer, serial num

ber, total capacity, number of drops, and lines installed.

(e) Switchboard protectors-kinds and number.

(f) Telephone protective apparatus.

(g) Clock-serial numbers and types installed. (h) Time-interval bells and interrupters.

(i) Firing signals.

(k) Zone signals.

(1) Meteorological equipment.

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(m) Terminal and outlet boxes, cut-out cabinets, and watertight telautographs to be examined for evidence of condensation. (n) Miscellaneous fittings.

(11) The aerial system should be carefully inspected and the condition of terminal boxes noted. There should be enough switchboard protectors for all lines; all protectors clean and free from dust, and a supply of extra fuses on hand. Inspection should be made of all manholes to see that the cables are properly racked up and are not so placed as to be liable to injury by workmen who may have access to them.

(12) Each telephone instrument in the aerial system should be provided with an efficient lightning arrester, and it should be especially noted that all arresters are properly grounded.

Inspectors should test the voltage and condition of the battery at each local battery instrument.

Wet cell types of local battery are no longer issued. The No. 6 dry cell is the present standard.

(13) Note will be made of all cases where apparatus is being used under conditions not contemplated in its design or not authorized under existing orders.

(14) The inspector will note whether the telephone system conforms to General Orders, No. 97, War Department, May 25, 1906, and report all instruments which are not installed in places prescribed by this order and all cases where the total number of telephones in use is in excess of the authorized allowance. In computing the allowance a band is counted as one organization.

Each post should have an extra wall telephone in the storeroom to replace any which become unserviceable.

(15) Tool equipments should be inspected and care taken to note any shortage or surplus, or the supply of tools not suited to maintenance work.

(16) Condition of surplus equipment.

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[graphic]

CPef C.

R. F. Barnes, Apr. 07.

THE NORRIS PETERS CO., WASHINGTON, D. C.

(17) Inspectors will examine telephone equipment for rifle ranges, reporting condition of instruments, cable, outlet boxes, etc.

(18) The inspector will close his report with a brief statement of the efficiency of the system as a whole, followed by specific recommendations looking to the correction of any defects which he may point out. These recommendations should include an estimate of the material and labor necessary to make any additions, alterations, or repairs deemed necessary.

CONSTRUCTION OF TELEPHONE SYSTEMS AT INTERIOR POSTS.

456. There are two classes of construction for post telephone systems, viz, aerial and subterranean. Aerial construction will be provided for the majority of posts; subterranean construction will be provided only for large posts where it is assured that garrisons will be maintained for many years in the future. It is expected that the post signal officer will secure a detail from the garrison to assist Signal Corps men installing either aerial or subterranean post telephone systems.

457. Approved aerial construction. The outside line construction of aerial systems must conform to the best standard commercial practice. Approved pole-line fittings are illustrated in drawing number 582 included in this manual.

Telephone switchboard should be connected to the switchboard lightning protectors by standard switchboard cable; this is only supplied in twenty-pair; where there are more than twenty lines use more sections of this cable.

Connection from switchboard protectors to terminal poles outside should be by lead-covered aerial cable (both ends potheaded).

Lead-covered cable should be used as much as possible, reducing the size of the cable at convenient points and distributing to telephones. Both ends of each section of cable should be potheaded and connected to a "Cook" cable pole terminal (type T 5 adopted). These pole terminals are supplied in all sizes corresponding to number of pairs of conductors in lead-covered cables. For example, a twenty-pair cable may be connected to a fifteen-pair cable by using a T 5 pole terminal (size for twenty-pair), and five pairs of wires distributed to near-by telephones. See paragraph 433, this manual, for standard sizes of cable.

Estimates for cable of an aerial system should allow about 30 per cent more pairs of wires than the number of telephones will require; this will provide for spare conductors when some become defective and additional telephones may be authorized.

All cable pole terminal boxes should be provided with lightning arresters (all Cook type T5 are), and when installed the iron frame and ground strip should be joined to a heavy wire down the pole to a good earth connection for lightning.

Ten and fifteen pair cable may be supported on 1-inch messenger strand; all larger sizes should have 3-inch strand.

Use "bridle wire" to connect line wires on a cross arm to a cable pole terminal box; the bridle wire should be secured to the underside of cross arms by " cross-arm cleats" (wood), and several pairs of bridle wire are kept together passing down a pole by "bridle rings" (two sizes).

Use "outside twisted pair" wire for distribution from pole line to buildings.

Use " inside twisted pair" wire for all wiring to telephones inside of buildings.

Use either No. 12 or 14 copper wire rubber insulated for connecting the ground terminal of a lightning arrester to the earth.

Use Mason lightning arrester, fuse type, for each telephone. It should be placed in the circuit just inside the building where the wires enter.

Telephone wires should be placed some distance from all wires carrying power or lighting current; where they necessarily cross, pass the telephone wires through a porcelain tube. In case the telephone wires must parallel power wires in the same conduit or elsewhere, every telephone on such lines should be protected against "sneak currents" by a "Cook" B 4 lightning arrester.

The length of wood poles should be such that the lowest wires will be about 18 feet above the ground. Wood poles should be cut on the reservation, where possible.

The butts of wood poles before setting should be treated with pitch, carbolineum, or other suitable preservative.

After poles are erected and cross-armed, they should be painted; color to be as desired by post commander.

Detailed descriptions of pot headings and cable splicing may be found in Signal Corps Manual No. 3. When competent enlisted men of the Signal Corps are not available for cable splicing, application should be made for the hire of a civilian, stating probable number of days and rate of pay per day.

458. Telephone switchboards. For small post systems requiring fifteen lines or less, the "Sterling" local battery board is provided. This is supplied with fifteen drops installed, but may be increased to twenty. For systems of twenty lines and over, the "North electric" local battery switchboard is provided. This board may be increased to fifty drops.

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The primary telephone circuit for the switchboard operator in the "Sterling" and "North electric" switchboards is a closed circuit

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