The principle of operation of telephone cards

Карточки содержат электрически программируемое ПЗУ емкостью 256 * 1 бит с последовательной побитной выдачей информации и внутренним инкрементным счетчиком адреса. There are two basic types of smart phone card is an 8 pin and 6 pin to 6 pin is usually used five cards of contacts among the eight contact cards also found instances in which only 5 are used as contacts, the rest of the load. Cards contain an electrically programmable ROM 256 * a bit of a serial bit-information issue and incremental internal address counter. Подключение карт к компьютеру для считывания и записи в основном осуществляется через LPT порт. The write operation produces a change in the state of memory cells "in the same direction", the reverse change (deletion) interface cards are not provided. Connect card to your computer for reading and writing mainly via LPT port. многие карты не поддаются перезаписи т.к после первой записи пережигается предохранитель. Unfortunately many of the maps can not be overwritten because after the first record burn through the fuse. It is necessary to collect the emulator calling card.

Procedures performed kartofonom when calling.

1. Turn on the power.
2. Reset.
3. Read the first 8 bytes and determine whether the card is valid in the region, preserving them in memory (if necessary decoding).
4. Read the five-byte units and save in RAM. Checking the available memory card capacity unit which has been encoded in the first 8 bytes.
5. Turning off the power.

After receiving the signal of the called party answers:

1. Turn on the power.
2. Calculate address of the last bit is not written off. (About 1-3 seconds after pressing the "answer")
3. Reset.
4. Submission of the number of pulses. CLK corresponding to the last address bit is not written off.
5. Submission command WRITE.
6. Submission Team W \ C.
7. Read the first 8 bytes and determine whether the card is valid in the region, preserving them in memory (if necessary decoding).
8. Read the five-byte units and save in RAM. Checking the available memory card capacity units encoded in the first 8 bytes, check whether the unit decreased compared to the previous reading.

Turning off the power.

At the expiration of a minute, if the connection is not broken, then the action from first to ninth cycle is repeated.