CHAPTER 85

HEADING 85.17 - ELECTRICAL APPARATUS FOR LINE TELEPHONY OR LINE TELEGRAPHY INCLUDING LINE TELEPHONE SETS WITH CORDLESS HANDSETS ANDTELECOMMUNICATION APPARATUS FOR CARRIER-CURRENT LINESYSTEMS OR FOR DIGITAL LINE SYSTEMS; VIDEOPHONES.

97 COMMODITIES

-Telephone sets; videophones :

8517.11 - -Line telephone sets with cordless handsets

8517.19 - -Other

-Facsimile machines and teleprinters :

8517.21 - -Facsimile machines

8517.22 - - Teleprinters

8517.30 - Telephonic or telegraphic switching apparatus

8517.50 - Other apparatus for carrier-current line systems or for digital line systems

8517.80 - Other apparatus

8517.90 - Parts

The term " electrical apparatus for line telephony or line telegraphy " means apparatus for the transmission between two points of speech or other sounds (or of symbols representing written messages images or other data) by variation of an electric current or of an optical wave flowing in a metallic or dielectric (copper optical fibres combination cable etc.) circuit connecting the transmitting station to the receiving station. The heading covers all such electrical apparatus designed for this purpose including the special apparatus used for carrier-current line systems.

(I) TELEPHONIC APPARATUS

This includes :

(A) Telephone sets.

Telephone sets for making and receiving calls from other apparatus in the network. They consist of :

(1) The transmitter a microphone which converts sound waves into a modulated current.

(2) The receiver (headphone or earphone) which reconverts the modulated current into sound waves.

In most cases the transmitter and receiver are incorporated in a single moulding known as a hand-set.

(3) The bell or buzzer which gives warning of a call.

(4) The switching device which is usually operated by the hand-set being removed from or returned to a cradle.

(5) The dialling selector (e.g. of drum or push-button type) which enables the caller to obtain his connection.

When separately presented microphones and receivers (whether or not combined as hand-sets) and loudspeakers are classified in heading 85.18 while bells and buzzers are classified in heading 85.31. Other devices occasionally fitted to subscribers' telephones include devices for memorising a telephone number; devices for holding a connection on line while communicating with a person on another extension and those for listening-in to or breaking into other lines. Telephones may be mounted in several ways. Generally speaking they are either designed for wall mounting or are of the portable type for placing on tables etc. However there are special types (e.g. the military field-telephone; " parlophones " for buildings of which part may be of built-in design for fixing into walls; videophones for buildings which are a combination consisting essentially of a telephone set for line telephony a television camera and a television receiver (transmission by line); coin-operated telephones for public booths; sealed telephones for use in mines). The heading covers all kinds of telephone sets including those in which a telephone set (incorporating a selector and a hand-set) and a device for the transmission of recorded messages and sometimes the recording of incoming calls constitute an integrated unit.

(B) Non-automatic switchboards and exchanges.

Ranging from small switching panels to large exchanges these consist of a frame on which are mounted the various manual switching devices etc. Their principal components are :

(1) " Call " or " clear " indicators (flaps bells lamps etc.) for signalling to the operator that a call is being made or that a connection is no longer required.

(2) One or more operators' telephone sets. These are similar in structure to subscribers' sets but often specially mounted (e.g. microphone on chest- support and receiver in the form of a headphone set).

(3) Switching devices usually consisting of jacks or sockets mounted in a panel and plugs connected to a cord.

(4) Keyboards a series of key switches electrically connected to the plugs and cords and used to enable the operator to answer the caller supervise the progress of the call and note its completion. Switchboards and exchanges may be designed for wall mounting or for standing on the ground. In the latter case they may or may not be movable. They are used for private lines or for the public network.

These are of many types. The key feature of a switching system is the ability to provide in response to coded signals an automatic connection between users. Some types of automatic switchboards and exchanges consist essentially of selectors which select the line corresponding to the impulses received from thec alling sets and establish the connection. They are operated automatically either directly by the impulses from the calling set or via auxiliary apparatus such as

directors.

The different types of selectors (pre-selectors intermediate selectors final selectors) and where used the directors are often assembled in series and in roups of the same type on chasis which are then incorporated into the exchange on metal racks. Particularly in smaller-sized installations they may however all be mounted on a single rack to form a self-contained automatic exchange.

(II) TELEGRAPHIC APPARATUS

This is essentially designed for converting texts or images into appropriate electrical impulses for transmitting those impulses and at the receiving end receiving these impulses and converting them either into conventional symbols or indications representing the text or into the text or image itself. The most important types are as follows :

(A) Apparatus for transmitting messages e.g. :

(1) Morse or Morse-type keys used for transmitting Morse code etc. These are make-break switches in the form of a hand-operated lever the movements of which result in the production of electric impulses corresponding to the message to be transmitted.

(2) Dial or keyboard transmitters. In this apparatus combinations of impulses representing the message are transmitted by striking a key set in a dial or a keyboard each key corresponding to a letter figure or other sign. In some apparatus the keyboard is similar to a typewriter keyboard. This category includes Br‚guet Hughes Baudot etc. transmitters and non-automatic teleprinter or teletypewriter transmitters. This group also includes devices which combine a visual display unit a dialing selector used in obtaining a connection and a keyboard.

(3) Automatic transmitters (e.g. Wheatstone high-speed transmitters and automatic teleprinter or teletypewriter transmitters). This apparatus is operated automatically by paper tape previously perforated to carry the text for transmission.

(B) Receivers e.g. :

(1) Morse-type recorders which translate electric impulses into conventional igns (combinations of dots and dashes) printed on a paper tape.

(2) Sounders permit aural reception of code signals by the sounds made when a heavy electro-magnetic armature moves between and strikes two sounding plates.

(3) Printer-type receivers which print the message received directly on a tape or page in ordinary characters. This category covers inter alia teleprinter or teletypewriter receivers. In some cases the receiver and the transmitter apparatus are combined into one receiver-transmitter.

In some complex apparatus called " retransmitters " the signals are received on one line and retransmitted on another without the aid of an operator.

In these transmitters the electric impulses are produced by the operation of a special device which scans the text or the picture to be transmitted. In the receivers a photographic surface is exposed to a beam of light controlled by the electric impulses emitted by the transmitter.The ancillary photographic equipment used with this apparatus (e.g. developing equipment) falls in CHAPTER90.

(D) Special " telecomposing " apparatus for transmitting or receiving a facsimile of a perforated type-setting tape.

(E) Facsimile machines for the telecommunication of text or graphics over telephone lines. These machines which are connected to a telephone line consist essentially of a transmitter section incorporating a device for the dot-by- dot scanning of the original document and a receiver section incorporating a recording device (sometimes heat-sensitive). This equipment is suitable both for the transmission and automatic reception of copies.

(III) APPARATUS FOR CARRIER-CURRENT LINE SYSTEMS OR FOR DIGITAL LINE SYSTEMS

These systems are based on the modulation of an electrical carrier-current or of a light beam by analogue or digital signals. Use is made of the carrier-current modulation technique and pulse code modulation (PCM) or some other digital system. These systems are used for the transmission of all kinds of information (words data images etc.). These systems include all categories of multiplexers and related line equipment for metal or optical-fibre cables. " Line equipment " includes transmitters and receivers or electro-optical converters. Combined modulators-demodulators (modems) are also classified here. Similar apparatus used for radio transmission systems is excluded (heading 85.25 or 85.27).

PARTS

Subject to the general provisions regarding the classification of parts (see the General Explanatory Note to Section XVI) parts of the apparatus of this heading are also classified here.

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The heading also excludes :

(a) Perforating machines whether or not electric used to perforate paper bands ready for use in automatic telegraphic apparatus (heading 84.72).

(b) Induction coils for insertion in telephone or telegraph line circuits (heading 85.04).

(d) Telephone answering machines designed to operate with a telephone set but not forming an integral part of the set (heading 85.19 or 85.20).

(e) Separately presented cordless handsets (heading 85.25) and radiotelegraphic or radiotelephonic transmission and reception apparatus (heading 85.25 and 85.27).

(f) Electric bells or indicators (e.g. luminous indicators operated by the dial of a telephone) (heading 85.31).

(g) Relays (e.g. Baudot Creed or Picard relays) and switching equipment such as selectors for automatic telephone exchanges (heading 85.36).

(h) Insulated electric wire cable etc. whether or not fitted with connectors including cords with plugs for switchboards (heading 85.44).

(ij)Telephone call registers and counters (CHAPTER90).

(k) Carrier-current receivers and transmitters which form a single unit with analogue or digital telemetering instruments or apparatus or which together with the latter constitute a functional unit within the meaning of Note 3 to CHAPTER90 (CHAPTER90).

(l) Calculographs (time recorders) (heading 91.06).

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