The photophone ( also known as a radiophone ) is a telecommunications device which allowed for the transmission of both articulated sounds and normal human conversations on a beam of light.

Though there were contemporaneous experiments by others such as William Preece, Stubblefield has been proposed as a claimant for the invention of wireless telephony, or wireless transmission of the human voice, which would, however conflict with the four documented patents for the photophone, invented jointly by Alexander Graham Bell and Charles Sumner Tainter in 1880.

During this time, Tainter worked with the Bells on several inventions, amongst them the photophone and phonograph, which they developed into the Graphophone, a substantial improvement of Edison's earlier device, for which Tainter received several patents along with the Bells.

* The Electrical Exhibition in Paris awarded Tainter a gold medal for his co-invention of the photophone the previous year ( 1881 );

" Other papers on the photophone " E. T. Z.

* 1 April 1880: world's first wireless telephone call on Bell and Tainter's photophone ( distant precursor to fiber-optic communications ) from the Franklin School in Washington, D. C. to the window of Bell's laboratory, 213 meters away.

The world's first wireless telephone conversation occurred in 1880, when Alexander Graham Bell and Charles Sumner Tainter invented and patented the photophone, a telephone that conducted audio conversations wirelessly over modulated light beams ( which are narrow projections of electromagnetic waves ).

Bell and Tainter's photophone, of 1880.

* 19 February 1880: The photophone, also known as a radiophone, is invented jointly by Alexander Graham Bell and Charles Sumner Tainter at Bell's Volta Laboratory.

The oldest technical application of the photothermal effect is believed to be the photophone, a communication device invented by Bell ( 1880 ).

" Le photophone de M. Graham Bell ".

Describes the photophone work of Hammond V Hayes at the Bell Labs ( patented 1897 ) and the German engineer H T Simon in the same year.

* Plaque in Washington D. C. marking the successful Bell / Tainter photophone experiment

On the photophone.

Similar to free space optical communication, the photophone also required a clear line of sight between its transmitter and its receiver.

As for missionaries, even if they succeeded in getting into the country they probably would not be allowed to preach the Christian faith to the Burmans.

He had come to learn that a reputation for peculiarity allowed mere field officers a certain leeway at Court ; ;

But all the reports of this first embassy show that the two Savoyards were the heads of it, for they were the only ones who were empowered to swear for the king that he would abide by the pope's decision and who were allowed to appoint deputies in the event that one was unavoidably absent.

Greville proposed Quiney as the fittest man `` for the following of the cause and to attend him in the matter '', and at his suggestion the corporation allowed Quiney two shillings a day.

Actual mileage allowances are itemized reimbursements allowed employees for the use of personally-owned vehicles on state business at the rate of $.07 per mile.

If, in the trustee's judgment, `` reasonable market conditions '' did not prevail during any given year, he was to be allowed to petition the court for an extension of time within the ten-year period.

Citizens of the United States who, on April 15, are not in the United States or Puerto Rico, are allowed an extension of time until June 15 for filing the return for the preceding calendar year.

Taxpayers residing or traveling in Alaska are also allowed this extension of time for filing, but those residing or traveling in Hawaii are not allowed this automatic extension.

Military or Naval Personnel on duty in Alaska or outside the United States and Puerto Rico are also allowed this automatic extension of time for filing their returns.

The reactants for the gas phase experiments were first frozen out in a side-arm attached to the manifold and then allowed to distil slowly into the manifold of pre-cooled reaction cells before sealing off.

No detectable reaction was found at room temperature for reaction mixtures allowed to stand up to 5 hours.

The mixtures of sample plus cell suspension were allowed to stand at room temperature for 1 Aj.

For the albumin method, equal volumes of 30% bovine albumin, sample and 2% cells suspended in saline were allowed to stand at room temperature for 1 hr and then were centrifuged at 1000 rpm for 1 Aj.

Blood samples were allowed to clot at room temperature for 3 hr, centrifuged and the serum was removed.

After blotting out most of the saline around the sections, a drop of Af was layered over each of the sections, allowed to react for 30 minutes, and then washed with PBS for 15 - 30 minutes.

But within that framework he allowed for as much flexibility as possible.

In 1910 it required the convening of a special three-judge court for the issuance of certain injunctions and allowed direct appeals to the Supreme Court.

Section 203 of the United States Code voids an assignment of a claim against the Government unless made after it has been allowed, the amount due has been ascertained, and a warrant for its payment has been issued.

Moreover, all three representations must be squeezed comfortably into little more than the length Brumidi allowed for each one of his.

Upon completion of the purging step, additional initiator appropriate for the molecular weight of the sample desired is added, and the system is then warmed to the polymerization temperature, at which the reaction is allowed to go to completion.

For example, the introduction of FM stereo transmission allowed backward compatibility since new FM radio receivers could receive monaural signals generated by old transmitters.

It was a 5-bit code, with equal on and off intervals, which allowed telegraph transmission of the Roman alphabet and punctuation and control signals.

Hardware correction of spherical aberration for the high-resolution transmission electron microscopy ( HRTEM ) has allowed the production of images with resolution below 0. 5 angstrom ( 50 picometres ) and magnifications above 50 million times.

It was a 5-bit code, with equal on and off intervals, which allowed telegraph transmission of the Roman alphabet, punctuation and control signals.

Some manufacturers created systems that allowed their own equipment to interconnect, but each scheme used a different transmission rate, so one manufacturer's systems could not synchronize with those of another.

Although analog carrier systems existed that multiplexed multiple analog voice channels onto a single transmission medium, digital transmission allowed lower cost and more channels multiplexed on the transmission medium.

An emphasis on oral transmission as more important than the printed word derives from the earliest period of Indian Buddhism, when it allowed teachings to be kept from those who should not hear them.

In 1992, Taito announced a CD-ROM-based console system named WOWOW, that would have allowed people to play near-exact ports of Taito's arcades ( similar to the Neo Geo ), as well as download games from a satellite transmission ( as the Satellaview would do later ).

Automatic Repeat reQuest ( ARQ ), also known as Automatic Repeat Query, is an error-control method for data transmission that uses acknowledgements ( messages sent by the receiver indicating that it has correctly received a data frame or packet ) and timeouts ( specified periods of time allowed to elapse before an acknowledgment is to be received ) to achieve reliable data transmission over an unreliable service.

Extensive use of third-party parts ( which finally allowed UAZ to replace its notorious transmission with a better, Korean-manufactured one ), large capacity, good off-road capabilities and affordable price (< 15, 000 USD ) predict good sales in Russia.

The device allowed for the transmission of sound on a beam of light.

This allowed higher transmission speed without data loss and without requiring such frequent attention from the computer.

The small low-power transmitter only allowed a data transmission rate of 2, 048 bits per second, though the system performed data compression to squeeze more information through the narrow bandwidth.

High-voltage AC transmission allowed hydroelectric power to be conveniently moved from distant waterfalls to city markets.

This allowed the torque shaft to clear the rotary base junction, which provided electrical power to turn the turret, while connecting to the transmission box mounted in the hull between the driver and radio operator.

This provides an infinitely variable speed control from 0 ground speed to what ever the maximum speed is allowed by the gear selection of the transmission.

This allowed Buehrig to dispense with the driveshaft and transmission tunnel ; as a result, the new car was so low it required no running boards.

Originally, the use of HD Radio transmission on AM was limited to daytime only, and not allowed at night due to potential problems with skywave radio propagation.

In the United States, videoconferencing has allowed testimony to be used for an individual who is unable or prefers not to attend the physical legal settings, or would be subjected to severe psychological stress in doing so, however there is a controversy on the use of testimony by foreign or unavailable witnesses via video transmission, regarding the violation of the Confrontation Clause of the Sixth Amendment of the U. S. Constitution.

Later refinements in UHF transmitters minimized these effects and allowed stereo transmission for those stations.

The Maxidyne allowed a heavy Class 8 truck to be operated with a 5 speed ( Maxitorque ) transmission.