Viking 4in. in. Digital Clock Surface Mount - CL-SMD4

Viking Electronics CL-SMD4 Surface Mount Housing for CL-D4 Wireless Digital Clock

Overview

The CL-SMD4 is a surface mount enclosure purpose-built for the Viking Electronics CL-D4 4-inch wireless digital clock — the hardware solution when flush or recessed mounting is not an option and you need a clean, wall-mounted installation. If you are deploying the CL Series synchronized clock system across schools, college campuses, restaurants, churches, or any facility that requires consistent, RF-synced timekeeping, the CL-SMD4 (often searched as CL SMD4) is the companion piece that makes a surface installation look intentional rather than improvised.

The CL-D4 clock that the CL-SMD4 houses operates on 915–928 MHz frequency-hopping spread spectrum RF technology, receives a sync signal from the master clock transmitter, and immediately re-transmits that signal — functioning as a built-in repeater every minute. This means every clock in the chain stays synchronized, and the signal propagates further across large facilities without a dedicated repeater node. The CL-SMD4 enclosure itself measures 11" x 8" x 1.7", accommodating the CL-D4's 4-inch digit display in a compact, low-profile wall package.

Key Features

• Purpose-Built Fit for CL-D4: The CL-SMD4 is dimensioned specifically for the CL-D4 4-inch digital clock — no adapter plates, no improvised mounting. If you are installing CL-D4 units where walls can't be cored, this enclosure is the correct path.
• 915–928 MHz Frequency Hopping (via hosted CL-D4): Frequency-hopping spread spectrum avoids interference from other 900 MHz devices common in industrial and commercial environments — Wi-Fi, wireless sensors, DECT phones. In a busy RF environment like a school or restaurant, fixed-frequency systems can lose sync; FHSS maintains it.
• 1-Watt (30 dBm) RF Output, 3,300 ft Transmission Range: The CL-D4's built-in repeater, running at 1 watt, retransmits the sync signal up to 3,300 feet. In a multi-wing building or campus deployment, each clock extends the sync network — you need far fewer dedicated repeater nodes compared to lower-power alternatives.
• 90–230V AC Input Voltage: The wide-range AC input means the same unit works on any standard North American or international circuit without a transformer swap. Facilities with aging mixed-voltage infrastructure can deploy a single SKU sitewide.
• Operating Range 0°C to 50°C (32°F to 122°F): Suited to climate-controlled interiors — classrooms, dining areas, lobbies, corridors. Not rated for unheated warehouses or outdoor exposure; plan accordingly for any non-conditioned space.
• Storage Temperature –15°C to 70°C: Broader storage envelope means units can sit in a supply room or shipping container without heat damage before installation — a practical advantage for staged multi-site rollouts.
• FCC Part 15 Compliance: FCC Part 15 certification means legal operation on the 915–928 MHz ISM band in the United States without a site license. This matters for any deployment requiring documented RF compliance — schools and government facilities in particular.
• Low-Profile 11" x 8" x 1.7" Enclosure: The 1.7-inch depth keeps the wall profile minimal. In corridors or classrooms where a bulky box would be a snagging hazard or aesthetic issue, this form factor is meaningfully thinner than generic surface-mount electrical enclosures.

Integration & Compatibility

The CL-SMD4 is designed exclusively for use with the CL-D4 4-inch digital clock within the Viking CL Series wireless clock system. The CL Series ecosystem includes 2.5-inch and 4-inch digital clock variants, a master clock transmitter, and accessory housings — all operating on the same 915–928 MHz frequency-hopping platform. The built-in repeater function in every CL-D4 clock means the sync signal can chain through multiple clock nodes across a large facility without dedicated infrastructure. For facilities already using Viking paging or intercom systems, the CL Series integrates naturally into a broader facility communications and time management deployment. If your site requires recessed or flush installation rather than surface mounting, evaluate the alternate housing options in the CL Series accessory line. The CL-SMD4 is not compatible with the CL-D2.5 (2.5-inch clock) — confirm your clock model before ordering.

Frequently Asked Questions

Q: What clock does the CL-SMD4 work with?

A: The CL-SMD4 is a surface mount housing designed exclusively for the Viking Electronics CL-D4 4-inch digital clock. It is not compatible with the CL-D2.5 (2.5-inch) variant.

Q: What is the transmission range of the CL-D4 clock when installed in the CL-SMD4 housing?

A: The hosted CL-D4 clock transmits and retransmits the RF sync signal at up to 3,300 feet using its built-in repeater, at 1 watt (30 dBm) output power.

Q: What frequency does the CL Series system operate on?

A: The system uses frequency-hopping spread spectrum across the 915–928 MHz band, which provides resistance to interference from other devices in the ISM band and maintains reliable clock synchronization in busy RF environments.

Q: What are the power requirements for the CL-SMD4 installation?

A: The CL-D4 clock installed in the CL-SMD4 housing is powered by an included power adapter and accepts 90–230V AC input, covering standard North American circuits without a separate transformer.

Q: Is the CL-SMD4 suitable for outdoor installation?

A: No. The CL-D4 clock's operating temperature range is 0°C to 50°C (32°F to 122°F), and there is no weatherproofing rating specified. The CL-SMD4 is intended for climate-controlled interior installations such as schools, restaurants, churches, and campus buildings.

Q: Is the CL Series system FCC certified?

A: Yes. The system carries FCC Part 15 certification, authorizing operation on the 915–928 MHz ISM band in the United States without a site license.

Ted Perry

The CL-SMD4 is the piece that completes a clean surface installation of the CL-D4 in facilities where coring walls is not feasible — and with the CL-D4's 1-watt output and 3,300-foot repeater range, the clock does real work once mounted. For a school or multi-wing campus deployment, that built-in repeater function means each installed unit extends the sync network rather than terminating it.

Technical Highlights:

• 915–928 MHz FHSS: Frequency-hopping spread spectrum gives genuine interference resistance in shared ISM-band environments — important in schools and commercial kitchens where 900 MHz gear is common. Fixed-frequency alternatives drift out of sync in these environments; FHSS does not.
• 1 Watt / 30 dBm RF Output: Running at 1 watt puts the CL-D4 at the practical top of Part 15 power limits — the 3,300-foot range claim is credible for open-corridor environments. Expect real-world figures closer to 1,500–2,000 feet through multiple concrete walls.
• 11" x 8" x 1.7" Enclosure: The 1.7-inch depth is genuinely shallow for a surface-mount electrical enclosure. In a corridor with foot traffic, that depth difference versus a standard 3-inch box matters for both aesthetics and ADA clearance.

Deployment Considerations:

• The CL-SMD4 is sized for the CL-D4 only — confirm you are not ordering the CL-D2.5 (2.5-inch clock) variant, which requires a different housing. Mixing housing and clock models is a common field error on multi-site orders.
• Operating temperature tops out at 50°C (122°F). Mechanical rooms, loading docks, and any space without reliable HVAC are outside spec — the clock will drop sync reliability before it fails outright, which can be hard to diagnose remotely.

For a K–12 or university campus deploying synchronized time across classrooms, dining halls, and corridors, the CL-SMD4 paired with the CL-D4 is a practical surface-mount solution: low wall profile, repeater-capable, and FCC Part 15 compliant out of the box.