Comelit 4681 2MP Colour Audio/Video Intercom Unit
The Comelit 4681 is a colour audio/video intercom station purpose-built for Simplebus 2-wire systems in residential and light commercial deployments. It combines a 2MP colour camera with integrated two-way audio, echo-cancelling microphone, and sealed loudspeaker to provide a complete entry-point communication solution. The unit handles visitor verification and access control in a single wall-mounted endpoint, eliminating the need for separate video and audio hardware at entry gates or doors.
Key Features
- 2MP Colour Video: 1920×1200 resolution captures facial detail and clothing identification at entry points. Front-mounted adjustment allows field orientation without wall disassembly.
- Two-Way Audio with Echo Cancellation: Built-in microphone and sealed loudspeaker support clear duplex conversation. Echo-cancelling circuitry eliminates feedback during simultaneous talk-listen cycles.
- Direct Electronic Lock Release: 3A output drives standard 12V electric strikes without external relay. 10A relay-switchable contacts (C, NC, NO) allow daisy-chain control of secondary locks or gate operators.
- Programmable DIP Switch Control: 8-position DIP switches configure call routing, audio levels, and accessibility features (e.g., extended ring duration for hearing-impaired users) without firmware upload.
- Timed Lock Release & Door Status Input: Built-in timer holds electronic strike energized for user-defined duration. Door open indication input reports back to master station when entry is used (audit trail support).
- Compact Wall Mount Form Factor: 102mm W × 55mm H × 38mm D — fits standard residential door frame or gate pillar. White housing blends into typical entry architecture.
- 2-Wire Simplebus Protocol: Operates on Comelit Simplebus 2-wire field wiring (0.75mm² conductor, runs up to 100m). Integrates with Comelit 1210 power supply and all Simplebus master/sub-station models.
- Low Power Draw: 2W nominal draw — minimal demand on Simplebus power supply, allowing longer wire runs and more endpoints per supply unit than higher-power intercoms.
The 4681 is the endpoint video intercom for Simplebus 2W installations where residents or security staff need to see and speak with visitors before granting access. Unlike master stations (which sit in a central location and control multiple zones), the 4681 is mounted directly at the point of entry — front door, gate, or loading dock — and communicates bidirectionally with a remote Simplebus master panel or sub-station via two twisted-pair wiring.
Deployment scenarios include multi-unit residential complexes where each apartment building entrance has one 4681 connected to a shared master station in the foyer or lobby; small commercial properties (offices, retail, warehouses) using the 4681 at a single entry with visitor badge printing or access-list management on the master; and gated communities where the 4681 resides at the perimeter gate, with the master station in a guard booth or resident's home. In each case, the 2MP colour feed and microphone reduce false-entry attempts and provide security staff with real-time visual context before buzzing in visitors or delivery personnel.
Configuration is straightforward for integrators familiar with Simplebus logic. The DIP switches address the unit within the 2-wire bus topology and set audio gain, relay timing, and optional functions (e.g., automatic door unlock after successful PIN entry on the master station). No software tools or USB programming are required — all settings are jumper-based, making field reconfiguration fast and transparent to the end user. Comelit provides a quick-start laminate card with each unit; detailed programming tables are in the Simplebus system manual.
The 4681 carries a 2-year manufacturer warranty covering defects in material and workmanship. It is compliant with CE marking for audio/video equipment in EU installations and carries standard EMC/safety certifications for 12V low-voltage intercom systems. Comelit Simplebus architecture is proprietary — the 4681 does not interoperate with non-Simplebus systems or third-party intercoms, so system planning and topology must be confirmed before procurement. Integrators should verify that the existing or planned Simplebus master station has available sub-station or endpoint ports; if not, expansion modules or additional master stations may be required.
Marty AllisonPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
We've deployed the Comelit 4681 across residential complexes and small commercial sites where Simplebus 2W infrastructure is already in place or planned. What stands out operationally is the simplicity of the 2-wire topology — a single twisted-pair runs from the master station to the 4681, eliminating the network/IP overhead and configuration complexity that comes with IP intercoms. For building entry control in a managed residential or commercial environment, that trade-off (less flexibility, lower cost, zero IT involvement) is exactly right. The 2MP colour sensor resolves faces clearly at 1–2 metres, which is typical entry-vestibule distance. Echo cancellation on the audio path is noticeably better than older analogue intercom designs; simultaneous talk doesn't produce that hollow feedback or volume drop that frustrates residents and visitors. One caveat: the Simplebus ecosystem is closed. You cannot mix the 4681 with IP cameras, SIP-based intercoms, or cloud-based access platforms without a third-party gateway, and those gateways are rare and often proprietary. If the site will eventually migrate to an IP security infrastructure, a Simplebus investment is a dead-end — plan accordingly.
Technical Highlights:
- 2MP Colour CCD Sensor (1920×1200): Matches or exceeds typical HD (1280×720) detail; the extra resolution overhead allows capture of ID badges, vehicle licence plates (at short range), and facial features. On a 2-wire system with no bandwidth pressure, image quality is not compressed or compromised for bitrate.
- Echo-Cancelling Microphone & Sealed Loudspeaker: Typical analogue intercoms use a simple piezo speaker and ceramic microphone — they feedback and muddy at high volume. The 4681 uses a dedicated echo-cancel IC; in our experience, call clarity is noticeably better, especially in concrete or tiled entry lobbies where acoustic reflections are high.
- 3A Direct Strike + 10A Relay Contacts: The 3A on-board output drives most residential electric strikes (Yale, Sargent, HES 5000 series). The 10A relay allows you to stack a second strike, operate a gate motor, or control a modular lock bank without external relay cards. Integrated timing means the strike holds for your programmed duration (typically 3–10 seconds) without master-station supervision.
- 8-Position DIP Switch Configuration: No firmware updates, no cloud dashboard, no vendor lock-in on software. All call routing, audio levels, and function mapping are jumper-set. This is a feature: on-site customization is trivial, and there is no dependency on vendor support for configuration changes.
- 2W Power Draw: Simplebus 1210 power supply rated 2A @ 12V DC can support 6–8 of these units on a single supply (assuming short wire runs and negligible voltage drop). Contrast this with PoE IP intercoms (50–60W each), where you'd need dedicated infrastructure and network capacity planning.
Deployment Considerations:
- Simplebus 2W is a closed, non-IP ecosystem. Confirm that your entire intercom network is Simplebus before specifying the 4681. Mixing Simplebus with IP cameras or SIP intercoms on the same site requires middleware that Comelit does not officially provide.
- 2-wire field runs are limited to approximately 100m with 0.75mm² conductor before voltage drop becomes problematic. If your entry point is distant from the master station (e.g., a property boundary gate), verify wire gauge and run length before installation. Upgrade to 1.5mm² if the run exceeds 80m.
- The 4681 mounts on a standard electrical gang box (single-gang in width, though slightly deeper than typical switches). Verify wall construction and cable routing before committing to a location. The unit is rated for exterior wet locations (splash-resistant), but we recommend a small roof overhang or trim cowl in heavy-rain climates to protect the microphone inlet.
- DIP switch addressing must match the Simplebus topology diagram. If you have multiple 4681s on the same system, each must have a unique address. Misprogramming the switches results in call conflicts or no response; always consult the Simplebus master manual for your specific configuration before field commissioning.
- The sealed loudspeaker output is adequate for interior lobbies and sheltered exterior vestibules, but not for noisy factory floors or high-wind outdoor gates. If ambient noise exceeds 80dB, consider adding an external loudspeaker (Comelit offers a module for this) or routing audio to a paging system instead of relying on the built-in speaker alone.
The Comelit 4681 is the right choice for residential and light commercial sites already committed to Simplebus infrastructure, where simplicity and low capex outweigh the flexibility and scalability of IP-based systems. For integrators managing Simplebus portfolios, it's a standard workhorse endpoint. For new deployments or sites planning IP migration, recommend an IP intercom (Axis, Hikvision, or Dahua) instead. Explore the full Comelit catalog for other Simplebus components and accessories.
