# HID 37bit FAC Code & CN - (H10304)

Everything you need to understand HID 37bit FAC Code & CN - (H10304)

## Card format Overview

A proprietary 48-bit card format used in access control systems, featuring a unique structure composed of 16-bit site code and 19-bit card number, and 2 parity bits (even and odd), allowing for easy management and avoiding card number duplication for secure, contactless access.

## HID 37bit FAC Code & CN - (H10304) format properties

### Site Code

16 bits. The facility code range is 0 to 65,535.

### Card Number

19 bits. A unique serial number (0-524,287) for each card within that facility code.

### Even parity

Even Parity for Even parity over bits 12-28.

### Odd parity

Odd Parity for Odd parity over bits 29-47.

### Generate examples

Put in the values for this card format, we'll generate the results in a few different formats.

### Here's your example

| Format | Value |
| --- | --- |
| Hex | 10064000C8<br>Copy |
| Decimal | 68824334536<br>Copy |
| Binary | 000000000001000000000110010000000000000011001000<br>Copy | 
 
## The API that turns phones into key fobs.