125 kHz LF Proximity Cards & Fobs

EM4450 RFID card

125 kHz LF C-tier format

A compatible replacement for EM Microelectronic EM4450 / EM4550 (read/write 125 kHz memory) — a 125 kHz proximity credential, encoded by specification to read identically on your existing readers. Order single spares or bulk quantities at a fraction of OEM list pricing.

How the compatible EM4450 / EM4550 (read/write 125 kHz memory) works

The EM4450 / EM4550 (read/write 125 kHz memory) is a 125 kHz low-frequency proximity credential — the band most legacy prox readers use. Its data structure is Page-organized read/write 1Kbit LF memory. When you present a credential, the reader decodes that exact structure and passes it to your access-control panel as a card number it recognises.

We build the compatible EM4450 / EM4550 (read/write 125 kHz memory) by encoding the identical data structure onto a programmable T5577 / EM4305 chip. Once written, the reader cannot tell the difference between our credential and the original — it presents the same bits, the same facility code, and the same card number. That is what "compatible by specification" means: not a generic look-alike, but a credential engineered to read exactly as the original does.

To order, tell us the part number or format printed on your existing EM Microelectronic card, and our specialists confirm the encoding before anything ships. Bulk and reorder quantities are welcome — pricing is a fraction of OEM list, and every credential is verified to read on your existing equipment.

Also known as

EM4450 · EM4550 · M034

EM Microelectronic and all other brand and product names are trademarks of their respective owners. Security ID Systems is an independent manufacturer and supplier of compatible access-control credentials and is not affiliated with, authorized by, sponsored by, or endorsed by these companies. Brand and format names are used only to identify the systems our products are compatible with. MIFARE and DESFire are registered trademarks of NXP B.V.

EM4450 / EM4550 (read/write 125 kHz memory) — common questions

Is this a genuine EM Microelectronic card or a compatible one?

It is an independently manufactured compatible credential — engineered to the same specification as the EM4450 / EM4550 (read/write 125 kHz memory) so it reads identically on your existing readers, but it is not an EM Microelectronic-branded product. Security ID Systems is independent and not affiliated with EM Microelectronic; your access-control panel accepts the credential exactly the same way.

What chip is the compatible EM4450 / EM4550 (read/write 125 kHz memory) encoded on?

It is encoded on a T5577 / EM4305 programmable chip. That platform reproduces the original 125 kHz LF data structure precisely, so the credential presents the same information your readers already accept.

What frequency and format is the EM4450 / EM4550 (read/write 125 kHz memory)?

It operates on 125 kHz LF, using page-organized read/write 1kbit lf memory. Matching that exact frequency and data structure is what makes a compatible credential work — a card on the wrong band or bit length simply will not read.

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Order a compatible EM4450 / EM4550 (read/write 125 kHz memory)

Send the part number or a photo of your card and reader. We verify the encoding before production and ship worldwide — including the rare formats no one else lists.