T5577 Programmable Transponder Compatible Cards & Fobs
The universal 125 kHz blank: a rewritable transponder an integrator or facility programs once to its own open-format system — ideal spare stock for legacy formats OEMs no longer manufacture.
Does American Key Cards make T5577 Programmable Transponder compatible cards?
Yes — American Key Cards supplies unbranded T5577 Programmable Transponder compatible cards and key fobs (AKC T5577 Programmable Blank Card), encoded to your facility code and card-number range and ready to use on your existing Microchip (Atmel) readers. No hardware changes and no dealer account required.
- 125 kHz
- Frequency
- RFID — multi-protocol writable 125 kHz transponder
- Technology
- 1
- Bit format
- 2+
- OEM part nos.
- American Key Cards
- Order from
The T5577 is the Swiss-army blank of low-frequency RFID: a rewritable chip that can be configured to behave like whichever open 125 kHz format your installation uses, then carries that identity like any fixed credential. Its value to a facility or integrator is inventory simplicity and longevity — instead of stocking a dozen legacy card types, you keep one programmable blank and configure it to the system in front of you, which is a lifesaver for older open formats the original makers stopped producing years ago. We supply unbranded T5577 cards and fobs either blank for your own encoder, or pre-programmed to your open-format specification and verified before shipping. To be clear about scope: this is issuance stock for systems you own or manage on open formats — for secured, encrypted credential platforms, a writable blank is not the answer, and our explainer pages point you to the right ordering channel instead.
T5577 Programmable Transponder specifications
- System brand
- Microchip Technology Inc. (ATA5577C)
- Technology
- Passive RFID — multi-protocol writable 125 kHz transponder
- Frequency
- 125 kHz
- Credential platform
- ATA5577C (formerly Atmel T5577): 256-bit EEPROM user memory, 100,000+ write cycles, configurable modulation (ASK/FSK/PSK, Manchester/Biphase) and data rate, with Wiegand-style output emulation
- Bit formats
- User-programmable to match your own open-format 125 kHz system — the chip is configured once to your installation's format and then behaves like a fixed credential of that type
- OEM part numbers
- ATA5577C, T5577
Specifications reviewed August 2026
Our compatible T5577 Programmable Transponder credentials
American Key Cards manufactures unbranded credentials engineered to work with your existing Microchip (Atmel) readers — no hardware changes, encoded to your facility code and card-number range before they ship.
Full specifications, form factors and ordering FAQ: T5577 programmable cards & fobs
American Key Cards is an independent manufacturer of unbranded, compatible-by-specification credentials. We are not affiliated with, endorsed by, or sponsored by Microchip (Atmel), and we never supply OEM-branded product — for brand-original credentials, order from Microchip (Atmel) or an authorized dealer. Brand names appear only to identify compatibility, and all trademarks remain the property of their respective owners.
Where T5577 Programmable Transponder is used
- Programmable spare stock a facility configures to its own installed 125 kHz format
- Replacement credentials for open formats no longer in OEM production
- Access-control commissioning and system testing
- A single blank SKU an integrator keeps on the van to issue for any open 125 kHz system they service
Works with these readers
Related formats
You might also need
EM4100 (64-bit Read-Only)
The world's baseline 125 kHz credential: EM4100's 64-bit read-only ID, transmitted in Manchester-encoded ASK, is what most simple prox systems, time clocks, and gym doors actually run on.
View compatible cardsHID Prox H10301 (Standard 26-Bit)
The most widely deployed proximity format in North America: 26-bit Wiegand — an 8-bit facility code plus 16-bit card number — on the 125 kHz HID Prox platform, live on millions of doors.
View compatible cardsAWID 26-Bit
A 125 kHz proximity format that outputs standard Wiegand 26-bit data — facility code 1–255, card number 1–65,535 — over AWID's own air interface, found on decades of commercial and residential installations across the U.S.
View compatible cardsT5577 Programmable Transponder — FAQ
What is a T5577 blank used for?
It's a programmable 125 kHz credential you configure to your own open-format access system — handy as universal spare stock and as a replacement for open formats OEMs have discontinued. Program it once to your installation's format and it behaves like a standard credential of that type.
How many times can a T5577 be reprogrammed?
The EEPROM is rated for 100,000-plus write cycles, so in practice it's effectively reusable for the life of the credential. That rewritability is what makes it valuable as commissioning and spare stock.
Can a T5577 be used with secured smart-card systems?
No — it's a 125 kHz open-format device. Secured, encrypted credential platforms (the AES smart-card systems covered by our explainer pages) can't be served by a writable low-frequency blank, and we'll direct you to the correct channel for those rather than sell something that won't work.
Do you supply them blank or pre-programmed?
Either. Integrators often want blanks for their own encoders; facilities without programming gear can send us their open-format specification and we program and verify each unit before shipping so it enrolls on arrival.