Universal LF Fobs
T5577 Keyfob
Multi-Protocol 125 kHz RFID Fob
Quick answer
The rewriteable 125 kHz LF chip (Atmel / Microchip ATA5577) keyfobs are the broadest 125 kHz LF credential ProudTek offers — 330-bit EEPROM, seven data blocks, Manchester / Biphase / FSK / PSK modulation and RF/8-to-RF/128 data-rate configurability (ISO/IEC 18000-2 air-interface) yield ≥ 30 emulated protocol profiles including EM4100, EM4200, HID Prox H10301, Indala 26/27-bit, AWID, Kantech ioProx, Pyramid, Farpointe, Viking, Keri and Nexwatch. This is the integrator / locksmith / red-team / BSI-TR-02102 migration-bridge credential, shipped under documented commercial-use-case validation and a signed orderer-authorisation record.
- 30+ protocol emulation from a single chip — the widest 125 kHz envelope ProudTek supplies. EM, HID Prox, Indala, AWID, Kantech, Pyramid, Viking, Keri, Nexwatch all configurable via the T5577 block-0 configuration word.
- 330-bit rewritable EEPROM across 7 data blocks (Microchip ATA5577 datasheet) with 32-bit password lock + independent configuration-block lock — the integrator can seal the modulation profile while leaving the ID field rewritable.
- Industry-standard medium for locksmiths, security integrators, commissioning teams and authorised red-team audits — ProudTek validates every order against a legitimate commercial use-case envelope and records the orderer-site authorisation in the order file.
Used in these industries
Deployments where this product is referenced on our industry landing pages.
At a glance
Use these short answers to decide whether this page matches the project before moving into the detail.
Chip
Microchip / Atmel ATA5577 LF transponder 330-bit EEPROM across 7 user data blocks (224-bit user payload, config block, traceability)
Air interface
ISO/IEC 18000-2:2009 Type A — 125-134.2 kHz LF Data rate RF/8 to RF/128 configurable per emulated format
Next step
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Request quote and samples- Protocol emulation envelope (≥ 30)
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- EM4100 / EM4200 / EM4450 64/128-bit ID
- HID Prox H10301 26-bit, H10302 37-bit, H10304 37-bit + parity, Corporate 1000 35-bit / 48-bit
- Indala 26 / 27-bit, AWID 26 / 34-bit, Kantech ioProx 26-bit, Pyramid 37-bit, Farpointe 26 / 34-bit, Viking, Keri, Nexwatch
- Write protection
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- 32-bit password write-lock on the EEPROM
- Independent configuration-block lock (block-0) — seals modulation profile while leaving ID rewritable
- Per-block lock bits for fine-grained read-only / read-write partitioning
- Tooling ecosystem
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- Production RFID writers (Proxmark, ACR122L, HID Omnikey 5427) for bulk issuance
- CSV-driven encoding workflow with signed UID ↔ card-number mapping
- Hobbyist tools (Flipper Zero, ChameleonMini) work against the same chip but are not used in ProudTek production — auditability difference
- Commercial-use-case validation
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- Order intake records the orderer's site / domain / integrator authorisation
- Locksmith / integrator accounts reviewed on first order and re-validated annually
- Red-team / penetration-test orders require a signed engagement statement naming the authorising customer
- Housing
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- ABS (standard, 10+ pantone colours, keyring-moulded)
- Silicone (platinum-cured, IP68 per IEC 60529, Shore A 60) and epoxy drop
- Leather (LWG Gold tannery, 40 × 30 × 5 mm rectangle) for premium service-provider issuance
- Security posture (LF 125 kHz — stated honestly)
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- No cryptography at the air-interface layer; RF emission is readable by any 125 kHz reader
- Password-lock defends EEPROM write-access, NOT RF-layer eavesdropping
- BSI TR-02102-1 cipher-suite recommendations explicitly do not endorse 125 kHz LF — HF AES-128 is the forward path
- Multi-vendor consolidation
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- One T5577 SKU replaces 8-10 format-specific SKUs across an integrator's 40+ client sites
- On-site programming matches whichever reader is installed (HID / Indala / AWID / Kantech / Farpointe)
- Inventory investment drops by 60-80 % for integrators servicing heterogeneous-reader portfolios
- Red-team / audit use
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- Authorised penetration testing of 125 kHz reader fleets
- Deliverable typically recommends HF AES-128 migration (DESFire EV3 / Plus SE / iCLASS SE)
- Engagement paperwork retained in the ProudTek order file
- Logistics
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- MOQ 100 stock ABS / 200-500 silicone / leather / custom shape
- Lead time 3-5 business days stock / 5-7 pre-configured / 10-15 custom housing
- Every order includes signed UID list + protocol-configuration evidence
T5577 keyfob at a glance
T5577 vs EM4305 — when to specify which
Both are rewritable LF 125 kHz chips, both sit under ISO/IEC 18000-2, both carry a 32-bit password lock. The practical difference is the emulation envelope — which drives the decision for integrators servicing multiple reader fleets.
EM4305 (tenant-reuse / OSDP retrofit)
- 512-bit EEPROM; narrower block layout than T5577
- Emulates EM4100, HID Prox H10301, basic Indala / AWID — ~6-8 protocols
- 32-bit password write-lock; no independent configuration-block lock
- Typical fit: single-site multi-tenant residential, storage facility, OSDP v2.2 retrofit of a Wiegand panel
- Integrator stocks EM4305 when the client portfolio is LF-homogeneous (all HID Prox, or all EM4100)
- Slightly lower unit cost than T5577 at 100-500 qty
T5577 (universal integrator / locksmith inventory)
- 330-bit EEPROM across 7 blocks with finer-grained lock bits
- Emulates ≥ 30 formats — EM, HID, Indala, AWID, Kantech, Pyramid, Viking, Keri, Nexwatch
- 32-bit password + independent configuration-block lock (seal the modulation, leave the ID mutable)
- Typical fit: locksmith duplication, security integrator covering 40+ heterogeneous-reader sites, commissioning inventory, authorised red-team audits
- Integrator stocks T5577 when any of the client portfolio uses anything beyond the EM / basic-HID envelope
- Unit cost parity with EM4305 in bulk — no pricing premium for the broader emulation envelope
Quantified inventory-consolidation case for T5577
T5577 lifecycle — legitimate commercial envelopes
T5577 is the same chip hobbyist tools (Proxmark 3, ChameleonMini, Flipper Zero) use to demonstrate 125 kHz cloning. That is not a bug in the chip — it is exactly why integrators, locksmiths and authorised red-team teams need it. ProudTek stages the fob against the five envelopes below and records the orderer authorisation in every order file.
- Envelope 1 · Legacy-site retrofit
A building still running a 1998 HID ProxPoint reader has no first-party replacement fobs available. T5577 programmed to HID H10301 with the site's facility code closes the gap until the reader fleet is modernised. Orderer is the integrator of record for the building.
- Envelope 2 · Multi-vendor integrator consolidation
A security integrator responsible for 40+ client sites holds a single T5577 SKU and programs on-site to whichever reader is installed. The order file names the integrator account and the client portfolio is summarised in the annual re-validation review.
- Envelope 3 · Commissioning + test inventory
A reader-install team programs T5577 fobs to the expected production protocol, tests every reader on the new install, then re-uses the same fobs for the next commissioning job. Order line explicitly identifies 'commissioning inventory' and the fobs do not ship to end-users.
- Envelope 4 · Locksmith key-duplication service
Locksmiths offering RFID fob copying for residential common-area doors, storage-unit lockers and gym lockers use T5577 as the blank medium. ProudTek accepts these orders from locksmith accounts with a written commercial-registration; the service is legitimate when the customer owns the door and the protocol is 125 kHz LF.
- Envelope 5 · Authorised red-team / audit engagement
Reference deployments span multi-vendor-legacy, locksmith-duplication, reader-commissioning, red-team-audit and 30-protocol integrator-inventory T5577-keyfob programmes — quarterly audit cadence, annual hardware refresh and ongoing chip-family migration tracked across each vertical. red-team engagements require a signed statement naming the authorising customer, the outcome typically recommends migration to HF AES-128 (DESFire EV3 / Plus SE / iCLASS SE), and the T5577 fobs used in the exercise are retained in the engagement-evidence package rather than distributed.
Useful next pages
Use these linked product, guide and comparison pages to keep the next click specific and practical.
Related 125 kHz & LF-to-HF migration
Adjacent LF credentials plus the recommended AES-128 upgrade path.
FAQ
What is the difference between T5577 and EM4305?
Both are rewritable 125 kHz chips, but T5577 supports more modulation formats and protocol emulations than EM4305. T5577 can emulate virtually every 125 kHz protocol including HID Prox, Indala, AWID and Kantech, while EM4305 supports fewer formats. T5577 is the preferred choice when you need maximum protocol flexibility; EM4305 is adequate when you only need EM4100 emulation or basic HID Prox emulation.
Can T5577 fobs be locked to prevent tampering?
Yes. T5577 supports a 32-bit write password that must be presented before the chip accepts any write commands. Additionally, the configuration block can be locked separately, preventing changes to the modulation format while still allowing data block updates. For maximum security, apply both the write password and configuration lock.
What is the MOQ and lead time?
T5577 keyfobs in standard ABS housing: MOQ 100, lead time 3-5 business days from stock. Pre-programmed with your protocol configuration and facility code: MOQ 100, lead time 5-7 business days. Custom housing (silicone, leather, custom shape): MOQ 200-500 depending on housing type, lead time 10-15 business days.
Is it legal to order T5577 keyfobs that emulate HID Prox?
Yes, for the sites and credentials the orderer is authorised to administer. T5577 itself is a generic ISO/IEC 18000-2 chip and HID Prox H10301 is a published 26-bit format widely implemented by third-party vendors. ProudTek validates orders against legitimate commercial use cases — residential buildings the orderer manages, client sites where the orderer is the integrator of record, locksmith key-duplication services, audit and penetration-testing engagements, or migration programmes where T5577 bridges a legacy reader fleet. ProudTek does not knowingly supply cloned credentials for third-party sites the orderer does not administer.
How does T5577 compare to a Flipper Zero or Proxmark 3?
Flipper Zero and Proxmark 3 are reader/writer tools used to read an existing 125 kHz credential and write the captured data into a T5577 chip. T5577 is the storage medium, not the reader tool. For bulk-issuance workflows — where ProudTek is programming hundreds or thousands of fobs with a defined facility code and a sequential card-number range — a production-grade RFID writer driven by CSV input is faster and more auditable than a hobbyist tool. ProudTek delivers pre-programmed T5577 fobs with a signed UID-to-card-number mapping so the customer never needs the hobbyist tool in production.
Sources & references
Primary standards, OEM datasheets and regulatory documents cited by this article. All URLs were verified on the access date shown below.
- ISO/IEC 18000-2:2009 — Parameters for air interface communications below 135 kHz
Physical-layer standard for LF 125 kHz, applicable to T5577 and every protocol T5577 emulates.
- Microchip / Atmel ATA5577 125 kHz Read/Write Passive RFID Chip — product page
Vendor reference for the T5577 chip — 330-bit EEPROM, configurable modulation (Manchester, Biphase, FSK, PSK), 32-bit password and configuration-block lock cited in this SKU.
- HID Global 125 kHz Prox Card Format Reference (H10301 26-bit Prox, Corporate 1000)
Reference for the HID Prox H10301 26-bit and Corporate 1000 formats T5577 is programmed to emulate in integrator retrofit scenarios.
- SIA OSDP v2.2 — Open Supervised Device Protocol specification
Replacement for the legacy Wiegand 5-wire reader-to-panel interface — relevant to LF retrofit scenarios where T5577 keeps the credential envelope constant while the reader-to-panel link is upgraded.
- BSI TR-02102-1 — Cryptographic Mechanisms: Recommendations and Key Lengths
German federal cipher-suite recommendations explicitly favour AES-128 HF over unauthenticated LF — the migration pressure that caps T5577's security envelope.
- IEC 60529:2013 — Degrees of protection provided by enclosures (IP Code)
IP rating basis for silicone / epoxy waterproof T5577 housing variants.
- Directive (EU) 2015/863 amending Annex II to Directive 2011/65/EU (RoHS 3)
EU RoHS 3 restriction-of-hazardous-substances compliance for housing materials.
Proud Tek is a Shenzhen-based RFID & NFC manufacturer supplying hotel chains, transit operators, event venues and retail brands worldwide. Every order includes free samples, RF testing and dedicated project support.
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