UID-Writable & Programmable Blank Cards for the Trade

The Programmable Blank Line

A programmable blank is a credential substrate with a read-write chip and no data written to it. You receive it either in that untouched state — ready for your own encoder — or pre-encoded to the exact parameter set you supply at order. Either path gives your operation complete control over facility codes, card-number sequences, and issue-level fields without depending on a lock manufacturer's fulfilment chain.

Security ID Systems carries the two dominant 125 kHz rewritable chips — T5577 and EM4305 — plus a UID-writable 13.56 MHz range for high-frequency workflows. All three are available as ISO CR80 cards in standard 0.76 mm, thin 0.50 mm, or key-fob form factors, and all ship in trade quantities. For specialist smart card workflows, the JavaCard SmartMX blank card extends the line to contact and contactless Java-based platforms.

T5577 and EM4305 125 kHz Rewritable Blanks

The T5577 is the workhorse of the 125 kHz LF proximity market. It is a multi-page, multi-protocol chip that can be configured to output EM4100, HID H10301 26-bit, Indala, AWID, Pyramid, and dozens of proprietary formats — making it the correct substrate for the vast majority of LF compatible-credential work. Our T5577 guide details the page structure, modulation options, and how the chip negotiates with different reader types. Because the T5577 is field-writable, you can adapt your card stock to a new format at the encoder without re-ordering substrate.

The EM4305 is the direct rewritable successor to the read-only EM4100, sharing pin-compatibility and the same 64-bit data word. Where the T5577 suits broad multi-format applications, the EM4305 is preferred when the target system is natively tuned to EM-type modulation and a lower-cost per-unit matters. Our EM4100 vs EM4305 vs T5577 comparison guide covers which chip to specify for each scenario. The T5577 blank rewritable card and EM4305 writable card are both listed individually in the catalogue with form-factor and pack-size options.

Both chips support the password-protect function, which lets you lock the configuration block after writing — a standard practice for issued credentials. Neither chip imposes a minimum order for loose-blank supply, though volume pricing applies to trade accounts from 50 units.

UID-Writable 13.56 MHz Blanks

At 13.56 MHz, the UID-writable blank fills a specific need: systems that authenticate solely on the four-byte UID — the chip's serial number read at the ISO 14443-A anti-collision stage — rather than on a cryptographic sector. A 4-byte CSN 32-bit passthrough card is the right choice when the access panel simply reads and logs the UID without issuing a challenge. UID-writable blanks go one step further: the UID block itself is unlocked, so you can program a specific four-byte value rather than accepting the factory-assigned one.

This matters in two practical situations: systems that maintain a fixed UID whitelist where new cards must match existing registered numbers, and multi-site deployments where UID ranges are pre-allocated per zone. The MIFARE family guide explains where UID-only authentication sits in the hierarchy of 13.56 MHz credential security, and why some installations use it alongside sector-keyed MIFARE Classic or DESFire layers. For a deeper HF application — such as the Häfele Dialock HH key card or EV-charging credentials — a 7-byte UID or sector-based substrate is usually more appropriate.

UID-writable 13.56 MHz blanks ship in CR80 card form only; fob versions of the same substrate are available on request for orders of 100 units or more.

Loose or Pre-Encoded, in Bulk

Integrators and card bureaus with their own HID OMNIKEY, ACR, or equivalent desktop encoder typically order loose blanks and program on-site, which keeps fulfilment agile — you encode cards as jobs come in rather than holding a large finished-goods stock. Pre-encoded supply suits organisations that issue directly to end-users without an intermediate encoding step, contractors running a managed-access service, and situations where the job scope includes supply-and-install of a defined card run. Our bulk and wholesale compatible access card programme covers both models.

For pre-encoded orders, you supply: the target format (e.g. HID H10301 26-bit, Indala 27-bit, EM4100 64-bit), the facility code, the starting card number and the quantity, and — for formats with parity or issue-level fields — those parameters too. If you are uncertain which format your existing reader population expects, our trade programme for locksmiths and integrators includes a format-identification step before the production run. We also accept a sample card for read-back if format details are not documented.

Minimum bulk quantities are 25 units for pre-encoded cards and 10 units for loose blanks. Standard lead time on stock formats is two to three business days. For less common proprietary emulations or high-volume runs, lead times are confirmed at order.

• Loose blanks: ship unwritten, ready for your desktop encoder
• Pre-encoded: supply format, facility code, card-number range and we encode to spec
• Mix of loose and encoded within the same order accepted
• Dual-frequency (LF + HF) combo cards available for select format combinations
• White-label and custom print options available on minimum runs

Order Blanks for the Trade

Trade accounts — integrators, locksmiths, card bureaus and facilities managers responsible for multiple sites — receive volume pricing on blanks, dedicated format support and priority lead times. Account setup is straightforward: contact us with your typical monthly volume and the format families you work with most, and we confirm pricing and lead time before any commitment. There is no annual fee and no minimum monthly spend.

If your workflow includes specialist HF formats, consider adding the HiTag2 blank fob for PHILIPS HiTag2 installations, or the EV charge card substrate for charging-network credential management to your blanks account. Both are available loose and pre-encoded under the same trade terms. The full range of blank and programmable substrates is catalogued under all products.

Security ID Systems is an independent manufacturer and supplier of compatible access-control credentials and is not affiliated with, authorized by, or endorsed by HID Global, Assa Abloy, EM Microelectronic, Microchip Technology (Atmel), NXP Semiconductors, Häfele, or any other brand whose reader or system these credentials are designed to work with.