SimonsVoss & Active-Transponder Locks: What Can't Be Copied

What an Active Transponder Is — and Why It Differs from a Passive Card

Most access credentials — proximity fobs, Wiegand cards, standard 13.56 MHz smart cards — are passive devices. They carry no internal power source and respond only when energised by the reader's RF field. The reader supplies all the energy; the credential simply modulates that field to transmit a fixed or challenge-authenticated code. This is the architecture familiar from the vast majority of 13.56 MHz HF smart cards and low-frequency prox formats alike.

An active transponder reverses that relationship in one critical respect: it contains its own battery and actively transmits during a credential exchange. The SimonsVoss G2 transponder, for example, drives its own RF output at 25 kHz, managing a full bidirectional dialogue with the lock cylinder. Because the device initiates and sustains that dialogue using on-board power and a proprietary protocol stack, it behaves more like a miniaturised radio node than a passive tag. The architectural gap between a passive credential and an active transponder is not incremental — it is categorical.

This distinction has direct consequences for how the access-control market sources replacement credentials. A passive card format can, in principle, be sourced from any manufacturer capable of producing blanks that conform to the relevant RF and data layer. An active transponder is a manufactured device that must be provisioned by the system vendor, because the firmware, protocol state machine, and battery management are proprietary at every layer.

SimonsVoss System 3060 G2 Decoded

The SimonsVoss System 3060 is a wireless locking platform designed for retrofit installation in standard European door profiles. Lock cylinders contain no wiring — they communicate with management software over a mesh radio network and draw power from their own internal cells. The user credential that presents to these cylinders is the G2 active transponder, a key-fob-sized device operating at 25 kHz. Authentication is a proprietary bidirectional exchange: the lock and the transponder authenticate each other before the actuator moves.

SimonsVoss also fields a separate credential type within the same ecosystem: the HF SmartCard. This card operates at 13.56 MHz and is based on established chip architectures — specifically MIFARE and DESFire variants. The two credential types address different installation scenarios. The active transponder is the primary credential for the 3060 wire-free cylinders; the HF SmartCard is used at readers designed to process ISO 14443 traffic, such as those integrated into building-management or multi-technology panels.

Because the two credential types run on fundamentally different RF layers and protocol stacks, they are not interchangeable within the platform. A 3060 cylinder expecting a G2 active transponder will not respond to an HF SmartCard presentation, and vice versa. This segmentation is architecturally intentional and has clear implications for anyone auditing their credential stock or planning an expansion of an existing SimonsVoss installation. See our guide How to Identify Your Access Card or Key Fob Format if you are unsure which credential type your cylinders accept.

Why the Active Transponder Cannot Be Reproduced as a Compatible Credential

Three independent characteristics of the G2 active transponder combine to place it outside the scope of third-party compatible credential supply. First, the 25 kHz operating frequency is not a general-purpose RFID band with published standards; it is a proprietary channel defined and controlled by SimonsVoss. No blank transponder standard exists for it. Second, the device contains a microcontroller running firmware that manages the bidirectional authentication dialogue, battery supervision, and over-the-air provisioning. Reproducing this would require access to and re-implementation of that firmware — a task with no viable commercial path outside the OEM.

Third, the G2 transponder is provisioned — assigned to specific access rights within a SimonsVoss locking plan — by SimonsVoss Digital Locking System (DLS) software. The provisioning data is written to the transponder by the system owner using an authorised programming device. Even if a hardware-equivalent blank existed, the provisioning interface is proprietary. There is no industry-standard personalisation protocol that a third-party supplier could implement to write valid G2 access data.

This is an honest and important distinction to make clearly. Our guide Compatible vs Genuine Access Cards: An Honest Buyer's Guide covers the general framework, but the short version is this: active transponders belong to the category of credentials that are system-defined devices, not industry-standard blanks. We stock a wide range of formats within enterprise-proprietary and standard credentials, and we are straightforward about where the compatible path exists and where it does not.

The HF SmartCard Compatible Path

The SimonsVoss HF SmartCard presents a different picture. Because it operates at 13.56 MHz on MIFARE and DESFire chip architectures, it falls within the domain of industry-standard ISO 14443 smart cards. The SimonsVoss compatible smart card in our catalogue is a genuine-chip blank — built on genuine NXP silicon — that is compatible with SimonsVoss readers designed to process HF credentials. The credential carries no pre-loaded access data; it is enrolled into your SimonsVoss system by your system administrator using the same DLS software that manages all credentials in the locking plan.

This is the correct framing for all secured smart credentials in modern access control. The card itself is a hardware token; the access rights live in the system and are written to the credential during enrolment. A compatible blank is precisely that: a credential with the correct physical and RF characteristics to be accepted by the reader hardware and enrolled by the system software. Our SimonsVoss 3060 compatible smart card format follows this model exactly.

For facilities teams managing mixed-technology buildings — where a SimonsVoss HF reader sits alongside panels from other manufacturers — it is worth reviewing whether a multi-format credential can serve multiple readers from a single card. Our range of 13.56 MHz HF smart cards includes options that carry multiple application sectors. The MIFARE Family Explained guide is a useful reference for understanding which chip tier is appropriate for your reader's security requirements.

What to Do If You Need SimonsVoss Spares

For G2 active transponders — the 25 kHz battery-powered devices used with System 3060 wire-free cylinders — the supply route is the SimonsVoss authorised channel. There is no compatible third-party alternative, and any supplier claiming otherwise should be asked to demonstrate the operating frequency and protocol compliance of their product before purchase. Your SimonsVoss installer or the SimonsVoss regional distributor is the correct first call for replacement transponders and for DLS-assisted provisioning.

For HF SmartCard credentials compatible with SimonsVoss readers, Security ID Systems can supply compatible blanks in the quantities you need — from small top-up orders to multi-site bulk runs. If you are also managing credentials for other proprietary systems in the same building, we stock compatible formats for a broad range of platforms. Gallagher compatible proximity cards, Inner Range SIFER cards, and Inner Range compatible proximity cards are all held in our standard inventory. For sites with transit or contactless-payment integration, Sony FeliCa Standard credentials are also available.

If you are sourcing credentials for an office building or commercial tenant access deployment where multiple lock brands are in play, our team can advise on format compatibility and credential consolidation. Contact us with your reader make and model, or with the card or fob currently in use, and we will identify the correct compatible format from our range.

Security ID Systems is an independent manufacturer and supplier of compatible access-control credentials and is not affiliated with, authorized by, or endorsed by SimonsVoss Technologies.