Payphone Mechanics: An Investigation

[banerjeerupak]

The pay phones in which we have to drop the coin in and then we are able to make calls. These are often evident at railway stations and other places. Does anyone have any idea as to how they work?

 

[berkeman]

They're just a vending machine, where what is being vended is access to the phone network:

http://en.wikipedia.org/wiki/Vending_machine

 

[banerjeerupak]

i do understand that they are just vending machines. Could you tell me the mechanism which is used to recognise a particular type of coin in these sort of machines. Wikipedia does not have this info. I have also tried googling it.

 

[berkeman]

i do understand that they are just vending machines. Could you tell me the mechanism which is used to recognise a particular type of coin in these sort of machines. Wikipedia does not have this info. I have also tried googling it.

Go back to google, and google coin mechanism. You will get lots of helpful hits.

I do want to warn you, though, that if you are looking for ways to spoof coin-operated vending machines, you will get no further help here on the PF.

 

[zeitghost]

Go back to google, and google coin mechanism. You will get lots of helpful hits.

I do want to warn you, though, that if you are looking for ways to spoof coin-operated vending machines, you will get no further help here on the PF.

Ah.

Just think of the great careers and major industries that were spawned by phone phreaks... dear dead days beyond recall & all that...

 

[banerjeerupak]

I'm not trying to spoof anything. I was planning to use the same mechanism to operate a automated entry to parking lots for my minor project. I have been googling the stuff. The hits are not of much use, the mechanism is never explained enough to understand its working. Mostly it is vendors selling the stuff. Which is of no use to me.

 

[berkeman]

I'm not trying to spoof anything. I was planning to use the same mechanism to operate a automated entry to parking lots for my minor project. I have been googling the stuff. The hits are not of much use, the mechanism is never explained enough to understand its working. Mostly it is vendors selling the stuff. Which is of no use to me.

Fair enough. Okay, one of the things I noticed in the google search results that I pointed you to, and some other google searches I did with a couple other keywords added into the basic coin mechanism search, was that there were some patents listed in the hit list.

I'd figured that most coin operated mechanism details were probably kept proprietary by the manufacturers (both for spoofing and competition reasons), but the patent hits also implies that some of the details are disclosed in patents (no help against spoofing, but of some limited help against competition).

So I went to the general patent search website that I use:

http://patft.uspto.gov/netahtml/PTO/search-bool.html

and did a basic search on the two key words in the Title field: coin mechanism. That gave lots of hits that look like they should give you lots of ideas for your project. Here's the hit list from that search:

http://patft.uspto.gov/netacgi/nph-...1=TI&co1=AND&TERM2=mechanism&FIELD2=TI&d=PTXT

Best of luck with your project!