N-1000-II. Access Control Sys.

Simply, I like to restore old things.

  N - 1000 - II. Access Control System. Back to life.

  May be you, like I, have a such Access Control System in the building and it stopped working. From now on you have two options. Find an alarm / security specialist (company) or do everything yourself. The first option looks attractive, but:
- tech never come quickly, and even more, on time;
- they will tell you a long story that how old your equipment are;
- there is always found some very expensive part that must be replaced first, and so on.
If you know how it works, then it looks funny and the same every time.

  Suppose you decide to do it quickly and on your own. It's not difficult, and even more - interesting.

   Power check.

  The system runs from 16VAC transformer and converts it into +5V, -5V for a main board and 9V to charge 8V backup battery. If you turn off the transformer, the voltage must remain on the 8V battery (on the door) and the lithium battery (on the board) to maintain the memory.

  On the board, next to fuses, you will find a 10 Ohms resistor, which usually has a bad connection with the board. If this is the case, then restore it (you may need to install a jumper wire between fuse and one resistor's leg).

   Connections check.

  It never hurts, to check the connections. To do this a little consciously, the next photo.

  As you can see, the system is very simple. It takes a data from the card reader thru "DATA" and "CLOCK" lines. If it matches, the magnet turns off for 5 seconds and makes it possible to open the door. If not, nothing happens.

  The system constantly sends data via RS-232, regardless of whether there is a computer on the other end or not. Better to check it out.

  Theoretically, you can reprogram this device without leaving the 'Hyper Terminal'.

  The system works independently and does not require an external computer (via RS-232). The latter is necessary for programming (cards, time, etc.), monitor / check data and get a log file. Every time you run a card, information about card number and card's owner appears on the screen.

  If the card is registered, the message is highlighted in yellow, if not, then in red.

  OK. If everything is good, then the power up the system and everything will start working as before. If not, then:

   Deep RESET.

  Sometimes, though very rarely, the system loses settings that are stored in memory (backed up by a 3V lithium battery). If this happens, then you have to restart the system from scratch. To do this, you need a computer with a serial port (COM1). Usually the system has a connected computer that saves a log files, and program PCPACK (DOS based), which it does. So there are no problems.

  We are talking about a situation where the system loses names, card numbers, they are shown with wrong numbers, does not open doors (at regular time) or so on. The red message will confirm this.

  To restore the system, you must completely clear the memory and program it again. It's easy to do:
1. Turn off the main power (usually a wall-mounted transformer);
2. Disconnect the 8V lead acid battery and;
3. Remove 3V lithium battery from the socket.
  To be sure, wait 5 minutes, and then connect batteries back and then turn power on by connecting the wall transformer to power outlet.

  After returning power, the system will start immediately. The internal card's database will be empty and the time will be reset by default. It remains to upload settings from PC to the panel.

  The operator's name and password will enable you to move on.

  After that, press F4 twice (->'F4 - System control' -> 'F4 - Init. Panel' ) and update all information (database, time, int. settings, etc.) in the panel.

  The last screen will look like this. You have to press 'Enter' many times (answer yes, to all questions) and upload will be finished automatically.

  In general, this is all that needs to be done.

   The last, short check.

   Each card has a number. Usually it is printed on the corner, on the back side.

  Just run any card over card-reader and make sure that its real number appears on the screen.

  It's it.

   Addition or how it looks.

  It is interesting that all cards are arranged approximately identically. Inside the "loop antenna" and controller. Of course, there are no battery. The energy to run is received from a card reader.

  A similar RFID chip is in your XX passport. It is not necessary to disassemble passport's back cover, even if you know how to do it safely. Exactly, how it looks, you can see below.

  The main difference is only in the amount of information that is stored in the chip.

   Addition or how it works.

  The card-reader does not know anything about the presence of a card. But it must supply power, to the card, in any case. Therefore, it constantly sends pulses filled with a frequency of 125 kHz (for this particular card's setup) and waiting for respond. When you bring the card to the reader's face ...

  ... reader shut off the power pulses (125kHz), receive answer and decrypts it.  The process is primitive end easy to ... (wiped on demand).

  Sometimes it is necessary to know card's format or how many bits of information are in the chip. It's easy, especially since whatever happens in the reader, it converts RF data from the card, into code, which is transmitted via "DATA" and "CLOCK" wires to the panel.

  You can use an expensive analyzer, but any computer with a sound card does it better and faster. This requires two voltage dividers (100k & 1k) that would not burn audio input and software. I love the Visual Analyzer, the picture from which you see.

  This is an answer for the card with the internal number 3805. And the first thing we can see - it is a 34-bit card.

  The rest - for fun. If you put a binary template (3805d=111011011101b) on top, it becomes clear that the last bit is a parity bit, and before - card number.

   Only for confirmation - below is the answer from the card with number 44576.

  This is hard to believe, but there is no rocket science here. All as simple as possible.

  Nothing more.

In hard cases - let me know. The address is below.

09.21.2017  SK_Lab



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