In 1710 there were five churches in the Carolinas; in1722-1723they formed the presbytery of James Island, which (after 1727) went through the same struggle as the synod of Philadelphia in reference to subscription; and in 1731 the parties separated into subscribers and non-subscribers.
An exchange is a central station to which wires are brought from the various subscribers in its neighbourhood, any two of whom can be put in telephonic communication with each other when the proper pairs of wires are joined together in the exchange.
When the subscribers in a local area exceed a certain number, or when for some other reason it is not convenient or economical to connect all the subscribers in the area to one exchange, it is usual to divide the area into a number of districts in each of which an exchange is placed, and to connect these district exchanges together by means of " junction circuits."
These inter-area or long-distance lines, called trunk circuits in England, terminate at one exchange in each local area, and between that exchange and the various district exchanges junction circuits are provided for the purpose of connecting subscribers to the trunk lines.
This board was equipped with spring-jacks and annunciators (calling-drops) for the subscribers' lines, and with flexible cords terminating in plugs for connecting purposes.
The conversation was finished either of the subscribers could release the shutter of the clearing-out drop by turning his generator handle, and the operator thus notified of the fact removed the plugs and discontinued the connexion.
Several single switchboards like that described may be employed, each devoted to a certain section of the subscribers, and placed in care of an operator.
In these circumstances, when, as frequently will be the case, the person calling desires to be put in communication with a subscriber who belongs to another section, connexions must be established in the office between the two sections; this necessitates additional switchboard arrangements, and also increases the time required to put subscribers in communication with one another.
All the subscribers' lines are connected in order to jacks on the first two or three or four operators' positions, and these connexions are repeated or " multipled " upon each succeeding similar group of positions.
Hence this operator, when signalled in the ordinary way, can put any one of these subscribers in connexion with any subscriber whatever, without the necessity of calling upon another operator to make connexions.
The feature of the system was the provision of special service circuits, termed call-wires, for purposes of communication between the subscribers and the exchange operators.
This advance did not merely remove the primary batteries from the subscribers' stations; it removed also the magneto-generator, and at the same time it modified considerably the conditions governing the exchange operating.
With the adoption of relays the signalling between the subscribers and the exchange became automatic, and, with the introduction of the principle of double and automatic supervision on the cord circuits, it became possible for the operators to tell at any instant the state of a connexion.
8) a repeating coil is placed in the cord circuit, and when two subscribers are connected together the winding connected to the line of the subscriber who is talking for the time being acts as primary, and the other, which is in the line of the listening subscriber, as secondary.
When one of two subscribers connected together by this arrangement talks, the Exchange From the Post Office Electrical Engineers' Journal.
When both lamps glow, the operator, who thereby knows that both subscribers have restored their instruments, discontinues the connexion.
Of the calls originated at an exchange are for subscribers connected to other exchanges, and in these cases the junction plant forms a considerable fraction of the whole equipment.
At the outgoing end the circuits are multipled on the subscribers' switchboard, while at the incoming end they terminate in plugs on a special incoming junction switchboard upon which the subscribers' lines are multipled in the usual way.
Each of the subscribers controls a signal at A, and when either or both of the telephones are replaced, the action is indicated by the lamps there.
If there be a line free, or when the turn of the call is reached, particulars of the connexion wanted are passed to the distant end, and the trunk operators request the local exchanges to connect the subscribers by means of junction I F..?
The call is controlled by the trunk operators, the junction circuits being equipped in such a manner that the subscribers' signals appear at the trunk exchanges, from which point disconnecting signals are sent automatically to the local exchanges, when the connexions between the trunk and the junction circuits are removed.
In suburban and rural districts subscribers are usually served by means of bare wires erected upon wooden or iron poles.
The conductors used for subscribers' circuits are of copper weighing from 10 to 20 lb per mile.
Various methods of making the connexions between the large main cables and the subscribers are in use.
The company consented to free intercommunication between its subscribers and those of the Post Office, and undertook to charge rates identical with those charged by the Post Office.
I doubt, however, if the number of subscribers to an embossed edition of The Great Round World would ever be large; for I am told that the blind as a class are poor.