People love to eat out . How many time have you gone to a eating house and had to await for a table ? It used to be that someone would take your name and then yell out or call over an intercom when your board was quick . Some eatery still do this , but many now userestaurant pagers .
You ’ve probably see these devices . The pager is a small plastic box that the hostess bridge player to you when she takes your name . You are then free to roam about within the immediate vicinity of the restaurant . Eventually , the pager lights up or vibrates , signaling that your mesa is ready . You take the pager back to the stewardess and are result to your board .
In this edition ofHowStuffWorks , we will search these pager and how they figure out . You will ascertain about themaster transmitterand see the simple engineering science that operates the beeper itself . But first , lease ’s probe the basics of paging .
What is a Pager?
A pager is a very simpleradiothat listens to just one place all of the clock time . Aradio transmitterbroadcasts signals over a specific frequency . All of the pagers for that particular internet have a built - in receiver that is tuned to the same frequency spread from the transmitter . The beeper listen to the sign from the transmitter constantly as long as the beeper is turn on .
Each pager has a specific designation chronological sequence called aChannel Access Protocol ( CAP ) code . The pager listen for its unique CAP code . When it hears the computer code , it alarm the exploiter and may render additional information , depending on the beeper case .
There are five canonical pager character :
Regional and internal page networks set up towers , like those used forcell phone , to cover with child areas . On - land site paging systemslike the I used by eating house apply a little desktop transmitter . In the next plane section , we will take a close facial expression at this gimmick .
The Master Transmitter
To maneuver the beeper used for on - site folio expect amaster vector . The professional transmitter sends out the signal that the beeper are listening to . A adept analogy is to believe the master transmitter as aradio stationand the pagers asradiostuned into that post .
The existent frequency used by the master sender varies between various models and manufacturers . Their insurance coverage area can range from a few hundred feet to several sea mile , depending on the power of the transmitter . To page a customer , the hostess enters the numeric computer code for that beeper into the master sender . The air hostess may also select a specific option , such as the computer code for " table is ready " or the code for " lose beeper . "
Most overlord transmitters exhibit the last several pagers contacted . Some systems can handle up to 10,000 individual pager , much more than any restaurant should ever require ! A pop option is to plug in the master vector into thetelephone systemof the restaurant . This allows a hostess or other phallus of the eatery faculty to start a page from any phone in the system of rules .
The pager typically run onrechargeable batteries . A recharging post is used to reload the pager easily . For example , the JTECH pagers in the image above have a lot of metal contact on the bottom of each pager . These middleman are unite by screws to metal plates on the pager ’s circuit circuit card . The metal plate run to the battery pack . Also , the screw train of thought into expose metallic element balls on top of the pager . These metal balls advert the alloy contacts on the bottom of the pager stacked on top of that one . This put across power through to that pager , which then passes it on to the next and so on .
Inside a Restaurant Pager
Inside a typical eating house beeper is a very unsubdivided circumference board with just a few basic components :
A simple radio antenna , made from a coil of telegram wrapped around a metallic element core , pick up the signaling from the superior transmitter . This signaling is sent to the microprocessor , where it is compared against the CAP code for that pager . When the signal match the CAP code , the pager alerts the user using one or more of three method : audio , ocular or vibratory .
An audio alert usually play a tone or series of tones through a tiny piezoelectric verbaliser mounted directly on the circuit board of the pager . Some pager actually play a prerecorded phonation alarum , such as " Your board is quick . " In many pagers , a series of LEDs swank rapidly or but perch up when an warning signal is sent .
As for the pagers that vibrate when activated , at heart is a smallDC motor :
you could see that a small free weight is attach to the motor . This weight is mount up off - center on the motor ’s spindle . When the motor spin the system of weights ( at some 100 to 150 rpm ) , the off - inwardness mounting make a strong vibration .
There you have it . The next clip you have to wait for a mesa at a restaurant and the hostess reach you a beeper , you will have a whole young appreciation for the elegant yet simple technology that lets you wander while you wait .
