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Read/Write to RFID

I have a RFID card reader device from unknown company.
I'd like to read/write to it using any programming language.
My question: is there a general way to read/write cards (using C# as example)?
Do I need a specific driver/API for every RFID reader?

No, but without drivers you can try to read raw data from USB device and find out what it means. Actually there should be a GUID.
Here is the article/question reading data from a USB port which may help

C# compatible Finger print reader and receipt generator

I am planning to create School Management System in C# and I'm gonna provide these features:
Biometric attendance system
Fee Slip Printing
I did some search and found these 2 products (fits my needs, I think):
Finger Print Reader - ZK4500
Thermal Receipt Printer - XP200 (not official link)
I was about to order these products but I read on a website, Make Sure the Device is compatible with Programming language (in my case C#). I try to find the answer on Google but no luck! :(
I am totally hopeless and helpless but still happy :) because Stack Over Flow community is always here to help and give the right direction.
So, Here are my questions:
Does these devices are configurable with C#? (if possible, please share any helpful resource)
Is it better choice to use receipt printer instead of regular printer?
Is there any better alternative available for fingerprint reader and receipt generator?
PS: I wanted to keep the printer and fingerprint reader cost as low as possible so customer can afford it easily.

I don't know about the ZK4500, but I can guarantee you that the Digital Persona U.are.U series can be used with C#. The SDK can be purchased as part of a package or standalone. I don't know how many devices you need, but I can tell you that I've had fairly good experience with the U.are.U 4500. The scanners are $99 each, SDK not included.
It also comes with examples for implementation with C#. You can choose to let the SDK handle everything for you, which means capturing a print, finding minutiae points, and creating a biometric template for you, or you can capture the raw image and do your own processing. The examples also show how to store it in your database.
Another option if you are set on a particular scanner is the neurotechnology fingerprint SDK. It includes drivers for many scanners and I can verify that it works well with C#.
Yet another option is the Griaule Biometrics SDK. This SDK also supports C# and is easy to use. It does not include drivers and only officially supports 6 scanners. Additionally, it may be a bit more difficult to get these days because Griaule recently changed their website and ended support for the older SDK. They seem to offer new SDKs, but I haven't used their newer products.
Regarding receipt printers...can't help you there.

OCR for extracting text from cedula/passport C#

I'm looking for a Tesseract or Google's Vision API type of OCR which can help in extracting textual information in passport / ID card image, (which may be captured from mobile or may be scanned. Hence frame size may vary a little). I have been through several posts, and and found Tesseract as preferred solution.
I also tested my test data using Vision API, and got 99% accurate and satisfactory results. But I have following problems/requirements:
Problems:
Tesseract is the suggested solution that i found on most of the posts i had been through, but it gives very bad results, as frame may vary. I can't train data, and I'm okay with any paid library available to help me in my scenario.
Vision API gives accurate result, but my requirement is to not to use cloud based solution.
There are few providers, (eg, LeadTool, IdScan etc.) which provide this feature, but they use their scanners first to scan the passport. Hence their SDK works for their scanners device.
Summary: Is there any available (paid or opensource) c# library available, which takes passport/cedula image as input, and returns accurate text?. Any suggestion/help will be appreciated.

Company called MicroBlink created BlinkID SDK to scan passports, ID cards. It is not free for commercial usage, but free for development. Link to SDK's site HERE. Tesseract OCR tool may give you false results because you probably have not done any processing for an image before OCR scan, which is mandatory if you want a proper result, especially for images of passports and ID's and so on. For image processing you can use OpenCV (free), but it may take you time to learn computer vision and image processing (which are very rewarding actually).

I'm one of the developers in MicroBlink, which is a company specializing in development of barcode and OCR solutions.
Tesseract is indeed one of the options you have. The problem with Tesseract is that it's hard to set the right parameters to get really accurate OCR results. And you still need to implement the data extraction logic on top of the OCR results. And integration on iOS/Android requires two separate codebases.
Google Cloud Vision gives very accurate OCR result, but as you said, it performs image processing on server side, which raises privacy and security concerns regarding sending private ID information over the network to third parties.
There are other companies developing similar products with similar properties (server side, no data extraction, etc..)
MicroBlink's BlinkID is different in the sense that it performs all processing locally (without server side connection). It uses our proprietary machine-learning based OCR engine to ensure data is captured correctly. It supports MRZ, PDF417 barcodes, and scanning the front side of some ID documents (such as UK Driver's licenses, Malaysian IDs, EU IDs...). All ID data is parsed and verified according to country's standards with checksum validation.
BlinkID is provided as a native iOS, Android and Windows Phone 8 SDKs, Phonegap / Cordova plugins for iOS and Android, and Xamarin component (C#) for iOS and Android.
There are also server side library (available on request) which can run on Linux / Windows / MacOS and which has C API and that can be used from .NET application using C++/CLI. Our development team is here to help with the integration in a .NET app.
Please contact support#microblink.com for more information on the subject.

Asprise C# .NET OCR and Barcode Recognition SDK can recognize both normal text, MRZ data and barcodes on passports and other identity documents. The accuracy rate for MRZ data is extremely high.
You can simply pass input images in formats like BMP, JPG, PNG, PDF or TIFF.
Many government agencies use Asprise OCR to read passport MRZ information.
You may contact Asprise support to obtain a special evaluation version for your scenario.

Just a correction about LEADTOOLS needing to...
"use their scanners first to scan the passport. Hence their SDK
works for their scanners device"
This part is not correct. We do not make or sell any type of scanning device. LEADTOOLS SDKs can use different standard devices (Twain and WIA on Windows, Sane on Linux, and cameras on Android and iOS devices using the operating system's own APIs). The OCR and ID recognition is then done through software.

Listen on printer cable for print and save to image file?

I assume I would need a special centronics cable to do this, but is it possible to get the print data from the remote device and convert it to a image file in .Net?
thanks,
Jason

This has not much to do with .NET. First you need to have some "receiver" hardware and driver, then you need to know the protocol used (PCL, PostScript, or something completely different or proprietary), and only then you can start thinking about the platform where you process the data.
That said, it may be easier to capture the data directly on the remote device.

Doing a remote capture of an LPT connection would be rather difficult. Converting the print data into an image would probably be even more difficult. (PCL, Postscript, or one of many other formats.)
If you just need the ability to print to an image why not check out something like PDFCreator. I have used it on several occasions and it works great. You can even share the virtual printer out as a network share or LPR queue for remote printing. You can configure it to print to a standard share on a network. And later you could write a service that could move the images to FTP or send them over email. (Much less pain then trying to sniff LPT.)
More...
It may be possible to use something like a parallel LapLink cable between the computer that is currently attached to the printer and another computer. Using a setup like that you could try to sniff the data connection. The problem is some of the functions for printing will not work with a bi-directional data cable so it it possible you would have one heck of a trying to protocol sniff the printer data.
Parallel Port (PC)
LapLink Cable
Printer Cable
IEEE 1284-B
IEEE 1284-C
Centronics (36 pin)

If it's possible to get the device you want to capture from to print to a serial port it will be vastly easier to get the data stream into the PC. I've listed a couple of commercial solutions below and they all convert to serial to go to the PC. To get the data from the parallel port you've got to handle the hardware interface See LPTCAP, then you've got to read from the parallel port. See Parallel Port Central, look for the Programming heading about half way down.
Some commercial solutions are PrintCapture and Photologic.

fingerprint reader or thumb reader

I am wanting to develop an Automatic Attendance System using a thumb reader. When the user enters the office campus, they must put their thumb on to a thumb reader and is then marked as present.
Can anyone suggest a thumb reader that supports API for reading and comparing thumb-print images, so that I can easily integrate it with my attendance system.
I would prefer it if the device supports a Java API.
I have Google'd this a lot, but could not find any good answers.
I came across a Microsoft thumb reader,but i dint get enough information on it.
Does anyone can provide me offical site of Microsoft thumb reader.
Any online stiulator?

I work in company developing such systems. We've successfully used devices by Futronic, both USB (FS80) and ethernet (FS84). The latter provide means for comparison, but AFAIk they aren't very good.
We've used matching algorithms by Sonda Technologies, they are very robust and have good performance. They provide JNI-style java API.
We've also used ethernet sensors by this company, it has better capabilities for indication (LED or text LCD display, and sound) and operating external devices.