How the compatible Paradox (FSK prox) works
The Paradox (FSK prox) is a 125 kHz low-frequency proximity credential — the band most legacy prox readers use. Its data structure is FSK; data prefix 00001111 (vs HID 00011101); manufacturer code + facility + card number + Paradox-specific CRC; Some Paradox prox is standard 26-bit Wiegand. 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 Paradox (FSK prox) 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, matched to your facility code and card-number range.
To order, tell us the part number or format printed on your existing Paradox Security Systems card, along with your facility code and card-number range, 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
Paradox · Paradox prox · Paradox C704 · C704 · C705 · Paradox keyfob
Paradox Security Systems 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.