The **Cassi-Rusco** card format is a proprietary access control credential format commonly used in **legacy security systems**. It was developed to provide **secure and reliable** authentication for entry systems in commercial, industrial, and institutional buildings. The format is widely recognized for its **specific bit structure**, making it distinct from standard card formats like Wiegand.

Although newer access control technologies such as **MIFARE** and **DESFire** have gained popularity, many organizations still use Cassi-Rusco cards due to their **compatibility with older access control readers** and **established security protocols**.

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The Cassi-Rusco format originated as a proprietary access control technology designed to offer a more secure and controlled credential format than traditional magnetic stripe cards. It was widely adopted in commercial and government facilities where secure authentication was a priority. Over time, the **40-bit format** became a recognizable standard within older security systems, making Cassi-Rusco a trusted name in access control.

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The Cassi-Rusco card format remains relevant in the access control industry due to several factors:

- **Legacy System Compatibility** → Many older access control systems were designed to work exclusively with Cassi-Rusco cards.

- **Unique Bit Structure** → The Cassi-Rusco format uses a specific number of bits that differentiate it from other credential formats, enhancing system security.

- **Reliable Performance** → Offers stable and proven operation in high-security environments.

- **Restricted Duplication** → Unlike open-format cards, Cassi-Rusco cards have **proprietary encoding**, making unauthorized duplication more difficult.

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Cassi-Rusco cards have a **specific bit structure** that determines how credential data is stored and transmitted to a reader. While variations exist, the most common specifications include:

| Bit Position | Description |

| ------------ | ---------------------------------------------------------------------------- |

| 1 | **Leading Parity Bit** - Ensures data integrity in the first half of the bitstream |

| 2 - 20 | **Facility Code** - Identifies the organization or site using the card |

| 21 - 39 | **Card Number** - Unique identifier assigned to each cardholder |

| 40 | **Trailing Parity Bit** - Ensures data integrity in the second half of the bitstream |

Each card is encoded with a **facility code and a unique card number**, which the access control system uses to grant or deny access.

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Cassi-Rusco card readers function by using **radio-frequency identification (RFID) technology** to retrieve data from a card when presented to the reader. The decoding process follows these steps:

1. **Card Detection** → The reader activates and sends a signal when a card is placed within its proximity.

2. **Data Transmission** → The card's embedded chip transmits its **40-bit encoded data** wirelessly.

3. **Bitwise Manipulation & Error Checking** → The system performs **bitwise operations** to decode the encoded data verify data integrity using parity bits, ensuring the extracted information is correct.

4. **Bit Parsing** → The reader extracts and separates the **facility code, card number, and parity bits**.

5. **Data Conversion** → Some readers may convert the raw Cassi-Rusco format into **Wiegand or another standardized format** for compatibility with access control panels.

6. **Access Decision** → The extracted card number and facility code are compared against the access control database to determine if entry is permitted.

By performing **bitwise operations**, the system ensures that errors or data corruption do not affect access decisions. The reader processes the **facility code, card number, and parity bits** before relaying the validated data to the **access control panel**, where permissions are checked and access is granted or denied.

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Cassi-Rusco card readers are specifically designed to process Cassi-Rusco card formats. These readers interpret the **40-bit data** and transmit it to the access control panel for authentication.

- **Proprietary Format Support** → Designed to read **Cassi-Rusco bit structures**, ensuring compatibility with legacy systems.

- **Wiegand Output** → Many Cassi-Rusco readers output data in **Wiegand format**, allowing integration with modern access control panels.

- **Durability** → Typically built for **indoor and outdoor environments**, with resistance to dust, moisture, and tampering.

- **Limited Compatibility** → While Cassi-Rusco readers excel in supporting their proprietary format, they may **not be compatible** with other card technologies without a system upgrade.

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As access control technology evolves, many organizations are considering migration away from **Cassi-Rusco** cards and readers due to **security vulnerabilities and limited scalability**. Key reasons for upgrading include:

- **Enhanced Security** → Modern smart cards (such as **MIFARE DESFire** and **HID iCLASS**) offer **encryption and authentication protocols** that Cassi-Rusco lacks.

- **Wider Compatibility** → Newer systems support **multiple credential types**, including mobile access and biometrics.

- **Future-Proofing** → Upgrading to a modern access control system reduces reliance on aging proprietary technology.

Organizations transitioning from Cassi-Rusco often choose **multi-technology readers** that support both **legacy cards and modern credentials** to allow a **gradual migration** without immediate disruption to security operations.

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**The Cassi-Rusco card format has played a significant role in access control systems but is gradually being phased out in favor of more advanced technologies.** While it remains a viable solution for legacy systems, organizations should consider:

✅ **Evaluating system security risks associated with older card formats.**

✅ **Exploring modern access control solutions for improved security.**

✅ **Using multi-format readers to facilitate a smooth migration.**

For facilities still using Cassi-Rusco technology, **proper maintenance and security best practices** are essential to ensure continued effectiveness while planning for future upgrades.