Elise gave a few hand signals to her detail.
What the hell, if hand signals and the language of smiles could do the trick, she'd make a fine employee.
Elise and Dan were a good team, relaying hand signals and other silent communications with nothing more than a glance at each other.
In this manner the signals are read by ear.
Etymologically the word implies that the messages are written, but its earliest use was of appliances that depended on visual signals, such as the semaphore or optical telegraph of Claude Chappe.
When signals are to be sent from either station the operator turns the switch c out of contact with the stop b, and then operates precisely as in open circuit send '" i ing.
In such cases it is usual to employ a local battery to produce the signals, and to close the local battery circuit by means of a relay working.
The result is that the armature of the relay is attracted, and currents are sent through the sounder from the local battery, producing the signals from the distant station.
A method of recording signals in the Morse code, formerly used to a considerable extent, was to use a chemically prepared ribbon of paper.
It was found impossible to make the Morse ink writer so sensitive that it could record signals sent over land lines of several hundred miles in length, if the speed of transmission was very much faster than that which could be effected by hand, and this led to the adoption of automatic methods of transmission.
In Squier and Crehore's " Synchronograph " system " sine waves of current, instead of sharp " makes and breaks," or sharp reversals, are employed for transmitting signals, the waves being produced by an alternating-current dynamo, and regulated by means of a perforated paper ribbon, as in the Wheatstone automatic system.
Screw adjustments are provided for closing or opening the air gap between the electromagnets and armatures, for raising or lowering the siphon, and for adjusting the point of the siphon to the centre or side of the paper strip. The received signals are recorded on the paper strip in an undulating continuous line of ink, and are distinguished by the length of deviation from zero.
The amplitude of the signals can be varied in several ways, either by a shunt across the electromagnet, or by altering the tension of the controlling springs or by altering the air gap between electromagnets and armatures.
Up to too words per minute the signals are easily readable, but beyond that speed they are more difficult to translate, although experts can read them when received at zoo words per minute.
In the improved Pollak-Virag system the received signals are recorded in characters similar to ordinary handwriting.
A ray of light is directed upon the mirror, and the motion of the latter, due to the varying strengths and direction of the received currents, is made to write the transmitted signals upon a strip of bromide photographic paper about three inches wide.
This is obtained by causing one of them to send a series of signals from one particular key, while the operator at the other station adjusts his speed until he receives the same signal after shortcircuiting his electromagnet for ten revolutions.
If by any chance wrong signals are printed or the instruments get out of phase, the sender is stopped by the receiver sending a few signals, after which both type-wheels are again set to zero and correspondence continued.
At regular intervals a rotating arm on the distributor connects the five keys of each keyboard to line, thus passing the signals to the distant station, where they pass through the distributor and certain relays which repeat the currents corresponding to the depressed keys and actuate electromagnets in the receivers.
Each receiver is provided with five electromagnets corresponding to the five keys of the keyboard, and the armatures of the electromagnets can thus repeat the various combinations for all the signals allocated to the different combinations of the keys.
When a combination of signals has been received and the armatures have taken up their respective positions corresponding to the transmitting keyboard, certain mechanism in the receiver translates the position of the five armatures into a mechanical movement which lifts the paper tape against a type-wheel and prints the corresponding letter.
The signals must therefore be sent at regular intervals, and to ensure this being done correctly a telephone or time-tapper is provided at each keyboard to warn the operator of the correct moment to depress his keys.
At the receiving station electrical mechanisms record the signals once more as perforations in a paper strip forming an exact replica of the transmitting tape.
For working long submarine cables the apparatus ordinarily employed on land lines cannot be used, as the retarding effect of the electrostatic capacity of the cable is so marked that signals fail to be recorded except at a very slow speed of working.
The transmitted signals or electric impulses, which on a land line are sharply defined when received, become attenuated and prolonged in the case of a long cable, and are unable to actuate the.
The record of the signals given by this instrument was an undulating line of fine perforations or spots, and the character and succession of the undulations were used to interpret the signals desired to be sent.
The interpretation of the signals is according to the Morse code, - the dot and dash being represented by deflexions of the line of dots to one side or other of the centre line of the paper.
The heavier cores, with the consequent advance in speed of working attainable, have necessitated the introduction of automatic sending, the instruments adopted being in general a modification of the Wheatstone transmitter adapted to the form of cable signals, while the regularity of transmission thus secured has caused its introduction even on circuits where the speed cannot exceed that of the ordinary operator's hand signalling.
Owing to the difficulty of maintaining perfect balance on duplexed cables, curb sending is not now used, but the signals are transmitted by means of an apparatus similar to the Wheatstone automatic transmitter used on land lines and differing from the latter only in regard to the alphabet employed; the signals from the transmitter actuate a relay having heavy armatures which in turn transmit the signals to the cable; this arrangement gives very firm signals, a point of great importance for good working.
The special form of curb sender mentioned, termed the " Interpolator," has been devised so as to secure the correct re-transmission of any given number of consecutive elements of a letter which are of the same sign, for when signals are received at the end of a long cable the relay arm will not return to its zero position between consecutive elements of the same sign, but will remain on the respective contact surface during the whole time occupied by such consecutive elements.
The instrument consists of two cams, the form of which regulates the components of the curbed signal, one cam being for the dot element and the other for the dash element, which by their sequence give the letter signals; these cams, by means of clutches controlled by the relay, are mechanically rotated by clockwork, the speed of rotation being approximately adjusted to the rate of transmission of a single element, so that the requisite number of consecutive elements is transmitted corresponding to the duration of contact of the relay arm with the side controlling that particular element.
He was one of the first to perceive the vast changes which must ensue from the introduction of steam into the navy, which would necessitate a new system of signals and a new method of tactics.
Again, low speeds, light stock, less stringent requirements as to continuous brakes, signals, block-working and interlocking, road-crossings, stations, &c., tend to cheapness in working.
In certain respects, on the other hand, America has gone further than the United Kingdom, especially in the matter of automatic signalling, and in the operating of points and signals by electrical power or air-pressure instead of manual labour.
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.
These supervisory signals took the form of lamps and were placed on the keyboard in positions immediately adjacent to the associated cords.
In the same way the arrangements finally elaborated by Lodge and Muirhead consisted of a direct coupled antenna and nearly closed condenser circuit, and a similar receiving circuit containing as a detector the steel wheel revolving on oily mercury which actuated a siphon recorder writing signals on paper tape.
Long upheld by a box kite, and, employing a sensitive coherer and telephone as a receiver, he was able, on December 12, 1901, to hear " S " signals on the Morse code, consisting of three dots, which he had arranged should be sent out from Poldhu at stated hours, according to a preconcerted programme, so as to leave no doubt they were electric wave signals sent across the Atlantic and not accidental atmospheric electric disturbances.
In the course of this voyage he noticed that the signals were received better during the night than the daytime, legible messages being received on a Morse printer only 700 m.
To send signals the continuous or nearly continuous train of waves must be cut up into Morse signals by a key, and these are then heard as audible signals in the telephone.
An important modification of this method enables not only audible signals but articulated words to be transmitted, and gives thus a system of wireless telephony.
The signals were sent by cutting up the continuous hum in the telephone into long and short periods in accordance with the Morse code by manipulating the key in the primary circuit.
