barcode reader in asp.net mation. in Software

Create Code 128 in Software mation.

mation.
Scan Code 128 Code Set A In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Code 128 Code Set A Maker In None
Using Barcode generation for Software Control to generate, create Code-128 image in Software applications.
2. If the lock has been installed and is performing correctly, it would supply back the
Code 128 Code Set C Recognizer In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
Code 128 Code Set C Generator In Visual C#.NET
Using Barcode creator for VS .NET Control to generate, create Code 128A image in .NET applications.
expected information, in which case the software continues to execute.
Encode Code 128 Code Set A In VS .NET
Using Barcode creation for ASP.NET Control to generate, create Code 128B image in ASP.NET applications.
USS Code 128 Printer In VS .NET
Using Barcode maker for Visual Studio .NET Control to generate, create Code 128 image in .NET framework applications.
3. If the lock has not been installed or has been removed, the software does not get what
Making Code 128A In Visual Basic .NET
Using Barcode maker for VS .NET Control to generate, create Code 128A image in .NET applications.
GTIN - 128 Maker In None
Using Barcode maker for Software Control to generate, create UCC - 12 image in Software applications.
it is looking for and so it aborts. Typically, the software periodically queries the lock.
UPC-A Supplement 2 Encoder In None
Using Barcode maker for Software Control to generate, create UPC Code image in Software applications.
Create Barcode In None
Using Barcode creation for Software Control to generate, create bar code image in Software applications.
16.2.2 VARIOUS HARDWARE LOCK SCHEMES
Printing EAN / UCC - 13 In None
Using Barcode creation for Software Control to generate, create EAN13 image in Software applications.
Painting Code-128 In None
Using Barcode creation for Software Control to generate, create Code 128 Code Set C image in Software applications.
There could be many ways in which the software sends information to the lock and expects the return information, and this distinguishes one lock from another. A good lock should not only work as a deterrent against unauthorized proliferation, but should also protect against any hacking attempt. This can be achieved if the lock scheme has infinite combinations (just like a mechanical lock). If a lock scheme always sends one particular type of information and expects a particular return answer, it is no good, as
Make ISBN - 13 In None
Using Barcode drawer for Software Control to generate, create ISBN - 13 image in Software applications.
Reading Bar Code In Visual Basic .NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
INTRODUCTION 279
EAN 128 Drawer In Java
Using Barcode creator for Java Control to generate, create USS-128 image in Java applications.
Bar Code Generator In Visual C#
Using Barcode generator for .NET framework Control to generate, create bar code image in VS .NET applications.
this can be duplicated. Ideally, the lock should have infinite combinations, though in practice that may not be feasible. A good portable hardware lock system should offer the following features: Should connect to user ports such as the parallel port or the RS-232 port. Should derive power for the lock circuit out of these ports. Should have a large number of combinations so as to resist any duplication attempts. For the parallel-port-based locks, should offer a pass-through parallel port; i.e., the user should be able to connect other peripherals to the parallel port apart from the lock. 5. Application software should periodically detect the presence of the lock by communicating with it.
Barcode Printer In .NET Framework
Using Barcode creator for Reporting Service Control to generate, create barcode image in Reporting Service applications.
Universal Product Code Version A Reader In .NET Framework
Using Barcode scanner for VS .NET Control to read, scan read, scan image in .NET applications.
1. 2. 3. 4.
Paint Code 128 In Java
Using Barcode creator for Java Control to generate, create Code128 image in Java applications.
Decode UPC Code In Visual C#.NET
Using Barcode reader for VS .NET Control to read, scan read, scan image in Visual Studio .NET applications.
Figure 16.1 shows a security lock connected on the PC RS-232 serial port. This figure illustrates the circuitry to contain an AT90S2343 processor to indicate that, in principle, the lock could be implemented using this processor. The RS-232 port signals are used not only for communicating with the lock, but are also used to power the lock. The signals on the RS-232 port have 12-V or 12-V voltages. The application software (which employs the lock) should drive these signals (DTR and RTS in the figure) to 12 V which is then , stepped down to a suitable level for the purpose of powering the lock. The other signals illustrated, TxD, and the RxD, are transmit and receive data signals and can be used by the lock to receive and transmit data respectively. This establishes a basic infrastructure on which a given lock algorithm could be based. Of course, it is assumed that the circuit employed would support the needs of the lock algorithm. Another way to design the security lock on the PC parallel port is illustrated in Figure 16.2. This scheme is slightly more demanding than the RS-232 port. This is because usually a PC would have only a single parallel port, the use of which cannot be given up (printing, etc.) simply because you want to use it for a hardware lock! To alleviate this possible problem, people have come up with a concept called a pass-through parallel port, which essentially means that the parallel port is a shared resource among many peripherals. In my laboratory, a single parallel port is used to connect to a ZIP drive, an HP printer, and a PADS application software hardware lock, all working in quiet harmony.
RS-232
DTR RTS
Voltage Regulator
+5V +Vcc
TxD RxD
AT90S2343
FIGURE 16.1 A security lock on the RS-232 port of the PC.
280 AVR PROJECT 7: SECURITY DONGLE
Parallel Port
Data Port 25 pin D type Male Connector 25 pin D type female connector
Control Port
Pass-through Port
AT90S2343
Status Port
FIGURE 16.2 A security lock on the PC parallel port with a pass-through port.
The ZIP drive is connected first to the parallel port. The hardware lock goes on the passthrough port of the ZIP drive and the printer is attached to the pass-through port of the lock! So this means that the lock circuit in a parallel-port-based lock has to be extra smart compared to that in the RS-232-based lock.
16.3 How to Build an Electronic Lock
Now that we have covered the basics of electronic hardware lock requirements, let us see what it takes to build an electronic hardware lock. We have seen that the lock has a scheme that we call the lock algorithm. Then it must be possible to put that algorithm in the form of realizable hardware. Next, it must connect to one of the user ports for ease of operation. It must derive power from the port. It must use the port for communication with the application software (the software that is supposed to employ the lock) and most of all, the lock must offer pass-through capability. If we want to build a lock, we must have the lock algorithm. There are many possible lock schemes, from the very elementary to the very complex. An elementary, rather silly scheme (though of equal deterrence) could be a simple wire link from an output signal line of the PC port to an input signal line of the PC port. For the RS-232 port, that would mean shorting the TxD line to the RxD line. Whatever the PC transmits on the TxD line is received back by the PC on the RxD line. A level of complexity could be built into this scheme by delaying the signal back to the PC by using some kind of memory element. The lock receives the data byte and temporarily stores the byte before transmitting it back on the RxD line. The next level of complexity could be incorporated by employing more memory elements that store a sequence of data bytes received by the lock and then transmitting back in some sequence.
Copyright © OnBarcode.com . All rights reserved.