Kastle Systems Compatible Key Cards & Fobs

Kastle Systems Compatible Credentials

Kastle Systems is a managed cloud-access provider that controls credential issuance as part of its service contract. That closed-loop model works well for the building operator, but it creates a supply gap for tenants, employers, and facilities managers who need additional or replacement cards quickly — and without routing every order through the managed-access channel. Security ID Systems fills that gap with credentials that are fully compatible with Kastle readers and panels.

Our compatible cards and fobs are manufactured to the Kastle proprietary bit structure and supplied pre-encoded to the values your system is already programmed to accept. No firmware changes, no panel modifications, and no involvement from the building's access provider are required on your end — the credential is presented to the reader and the door opens exactly as it would with an original-issue card.

This page covers the 32-bit Kastle format in detail, explains why managed access creates the supply constraint most tenants encounter, and outlines exactly what information you need to provide when placing an order. For a fuller narrative on the managed-platform model and how Kastle credentials are produced, see our deep dive on Kastle Systems fobs and cards.

The 32-Bit Kastle Format

The Kastle proprietary format encodes four distinct fields into a 32-bit transmission: facility code, card number, issue level, and a Kastle-specific parity sequence. This is not a standard Wiegand format such as the widely documented HID H10304 46-bit or the common Lenel 42-bit structure — the parity algorithm and field boundaries are Kastle's own design. Readers programmed for Kastle will reject any credential that does not pass parity validation, which is why off-the-shelf 26-bit or generic proximity cards will not work in these systems.

Understanding the format also explains why this is a Tier-S supply — the 32-bit Kastle credential is rarely offered by generic access-card vendors. Security ID Systems has the format on file and can encode to any valid facility code and card-number range, including the issue-level field that some Kastle installations use to distinguish credential generations.

Kastle installations typically operate on 125 kHz LF proximity technology, placing these credentials in the same frequency family as standard 125 kHz LF proximity cards and fobs. The credential communicates passively when brought into range of the reader, with no battery or user interaction required.

The issue-level field deserves particular attention. Unlike facility code and card number, which remain stable across an installation's lifetime, the issue level can be incremented when a building refreshes its credential stock — for example, after a bulk loss event or a planned rotation. If your building has ever reissued credentials en masse, there is a good chance the active issue level differs from what was printed on the original card. Providing the correct current issue level is the single most common point of failure in self-sourced Kastle replacement orders, and it is one of the questions our order process specifically captures.

Why Managed Access Makes Spares Hard to Source

In a traditional access-control installation, the building owner or facilities manager holds the system credentials and can order replacements from any compatible supplier. Kastle's managed-access model differs: the access platform, credential database, and often the physical credential supply chain are all under Kastle's administration. Tenants typically cannot purchase additional fobs directly from a hardware distributor because the required encoding parameters — particularly the facility code and parity — are not published.

Security ID Systems operates as an independent supplier in the managed and cloud-access segment. We are not part of the Kastle service infrastructure, and credentials ordered from us are manufactured and encoded to your specifications independently. This is the same category of supply used for other managed-platform formats — for example, organisations running Verkada compatible access cards or Avigilon compatible credentials face a structurally similar sourcing challenge. Proprietary-format systems from other vendors in this segment — including Software House CCOTZ 37-bit and ADT 31-bit compatible proximity cards — all require the same approach: knowing the encoding parameters and working with a supplier that holds the format.

Our buyer's guide on compatible vs genuine access cards explains in practical terms what compatibility means, what information you need to provide, and how to confirm a compatible credential will function in your specific installation — useful reading before placing a first order for any proprietary-format system.

Encoded to Your Building

Ordering compatible Kastle credentials requires supplying the encoding parameters your installation uses. At minimum, this means the facility code and the card-number range you need. If your installation uses the issue-level field, that value must also be provided so the credential passes parity correctly. The format identification guide walks through how to retrieve these values from an existing credential or your access-control admin console.

Cards and fobs are encoded to order — we do not ship blank credentials for Kastle installations. This ensures that every credential we supply is ready to enrol in your system's cardholder database and present correctly at the reader without additional programming on your side. Order quantities start at individual replacement cards and scale to bulk runs for employers managing multi-tenant floors or high-turnover workforces.

For installations that use non-standard facility codes or tightly controlled card-number sequences, we also recommend reviewing our guide to corporate custom facility codes and FlexSecur formats — it covers the documentation typically needed to ensure accurate encoding for formats where the bit structure is not publicly standardised, which applies directly to the Kastle 32-bit format.

Credential Form Factors and Practical Considerations

Compatible Kastle credentials are available in two form factors: ISO-sized clamshell card and standard key fob. The clamshell card fits ID-card holders and badge reels and is the most common choice for office tenants who carry the credential alongside other building-access cards. The key fob attaches to a keyring and is the preferred option for residential tenants and employees who do not carry a badge holder.

Both form factors carry identical electrical performance at 125 kHz: read range is determined by the reader's antenna, not the credential type, so substituting a fob for a card — or vice versa — does not affect the read distance you experience at your specific readers. If your building uses combination readers that accept both cards and fobs, either form factor will function at the same range.

Durability is worth noting for high-turnover environments. The clamshell card format encases the antenna and chip in a rigid PVC shell that resists the flexing damage common in wallet-carried credentials. Key fobs use an overmoulded housing that protects the internal assembly from the mechanical stress of everyday keyring use. Both are manufactured to standard commercial tolerances for access-control credentials and are not rated for industrial wet environments.

If your organisation is issuing credentials to a mix of staff categories — some carrying lanyards and badge holders, others on keyrings — you can specify a split quantity across both form factors in a single order. Each credential is individually encoded to its assigned card number, so the cardholder database enrolment process is identical regardless of form factor.

Request a Kastle Quote

To receive a quote for compatible Kastle Systems cards or fobs, use the contact form and include your facility code, required card-number range, and preferred credential form factor — ISO card, clamshell card, or key fob. Indicate whether your installation uses the issue-level field and, if so, which value is active. Bulk pricing applies to orders of ten credentials or more.

Security ID Systems is an independent manufacturer and supplier of compatible access-control credentials and is not affiliated with, authorized by, or endorsed by Kastle Systems.